drm/amd/display/dc/dce100/dce100_resource: Make local functions and ones called by reference static

Fixes the following W=1 kernel build warning(s):

 In file included from drivers/gpu/drm/amd/amdgpu/../display/dc/dce100/dce100_resource.c:54:
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce100/dce100_resource.c:614:22: warning: no previous prototype for ‘dce100_link_encoder_create’ [-Wmissing-prototypes]
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce100/dce100_resource.c:653:32: warning: no previous prototype for ‘dce100_opp_create’ [-Wmissing-prototypes]
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce100/dce100_resource.c:668:17: warning: no previous prototype for ‘dce100_aux_engine_create’ [-Wmissing-prototypes]
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce100/dce100_resource.c:706:20: warning: no previous prototype for ‘dce100_i2c_hw_create’ [-Wmissing-prototypes]
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce100/dce100_resource.c:721:22: warning: no previous prototype for ‘dce100_clock_source_create’ [-Wmissing-prototypes]
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce100/dce100_resource.c:745:6: warning: no previous prototype for ‘dce100_clock_source_destroy’ [-Wmissing-prototypes]
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce100/dce100_resource.c:834:6: warning: no previous prototype for ‘dce100_validate_bandwidth’ [-Wmissing-prototypes]
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce100/dce100_resource.c:879:16: warning: no previous prototype for ‘dce100_validate_global’ [-Wmissing-prototypes]

Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Leo Li <sunpeng.li@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Anthony Koo <Anthony.Koo@amd.com>
Cc: amd-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dce100/dce100_resource.c

@@ -611,7 +611,7 @@ static const struct encoder_feature_support link_enc_feature = {
 		.flags.bits.IS_TPS3_CAPABLE = true
 };
 
-struct link_encoder *dce100_link_encoder_create(
+static struct link_encoder *dce100_link_encoder_create(
 	const struct encoder_init_data *enc_init_data)
 {
 	struct dce110_link_encoder *enc110 =
@@ -650,7 +650,7 @@ static struct panel_cntl *dce100_panel_cntl_create(const struct panel_cntl_init_
 	return &panel_cntl->base;
 }
 
-struct output_pixel_processor *dce100_opp_create(
+static struct output_pixel_processor *dce100_opp_create(
 	struct dc_context *ctx,
 	uint32_t inst)
 {
@@ -665,7 +665,7 @@ struct output_pixel_processor *dce100_opp_create(
 	return &opp->base;
 }
 
-struct dce_aux *dce100_aux_engine_create(
+static struct dce_aux *dce100_aux_engine_create(
 	struct dc_context *ctx,
 	uint32_t inst)
 {
@@ -703,7 +703,7 @@ static const struct dce_i2c_mask i2c_masks = {
 		I2C_COMMON_MASK_SH_LIST_DCE_COMMON_BASE(_MASK)
 };
 
-struct dce_i2c_hw *dce100_i2c_hw_create(
+static struct dce_i2c_hw *dce100_i2c_hw_create(
 	struct dc_context *ctx,
 	uint32_t inst)
 {
@@ -718,7 +718,7 @@ struct dce_i2c_hw *dce100_i2c_hw_create(
 
 	return dce_i2c_hw;
 }
-struct clock_source *dce100_clock_source_create(
+static struct clock_source *dce100_clock_source_create(
 	struct dc_context *ctx,
 	struct dc_bios *bios,
 	enum clock_source_id id,
@@ -742,7 +742,7 @@ struct clock_source *dce100_clock_source_create(
 	return NULL;
 }
 
-void dce100_clock_source_destroy(struct clock_source **clk_src)
+static void dce100_clock_source_destroy(struct clock_source **clk_src)
 {
 	kfree(TO_DCE110_CLK_SRC(*clk_src));
 	*clk_src = NULL;
@@ -831,7 +831,7 @@ static enum dc_status build_mapped_resource(
 	return DC_OK;
 }
 
-bool dce100_validate_bandwidth(
+static bool dce100_validate_bandwidth(
 	struct dc  *dc,
 	struct dc_state *context,
 	bool fast_validate)
@@ -876,7 +876,7 @@ static bool dce100_validate_surface_sets(
 	return true;
 }
 
-enum dc_status dce100_validate_global(
+static enum dc_status dce100_validate_global(
 		struct dc  *dc,
 		struct dc_state *context)
 {