drm/amd/display/dc/dce60/dce60_resource: Make local functions static

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

 drivers/gpu/drm/amd/amdgpu/../display/dc/dce60/dce60_resource.c:522:17: warning: no previous prototype for ‘dce60_aux_engine_create’ [-Wmissing-prototypes]
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce60/dce60_resource.c:560:20: warning: no previous prototype for ‘dce60_i2c_hw_create’ [-Wmissing-prototypes]
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce60/dce60_resource.c:576:20: warning: no previous prototype for ‘dce60_i2c_sw_create’ [-Wmissing-prototypes]
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce60/dce60_resource.c:710:22: warning: no previous prototype for ‘dce60_link_encoder_create’ [-Wmissing-prototypes]
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce60/dce60_resource.c:749:22: warning: no previous prototype for ‘dce60_clock_source_create’ [-Wmissing-prototypes]
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce60/dce60_resource.c:773:6: warning: no previous prototype for ‘dce60_clock_source_destroy’ [-Wmissing-prototypes]
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce60/dce60_resource.c:863:6: warning: no previous prototype for ‘dce60_validate_bandwidth’ [-Wmissing-prototypes]
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce60/dce60_resource.c:908:16: warning: no previous prototype for ‘dce60_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: Mauro Rossi <issor.oruam@gmail.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/dce60/dce60_resource.c

@@ -519,7 +519,7 @@ static struct output_pixel_processor *dce60_opp_create(
 	return &opp->base;
 }
 
-struct dce_aux *dce60_aux_engine_create(
+static struct dce_aux *dce60_aux_engine_create(
 	struct dc_context *ctx,
 	uint32_t inst)
 {
@@ -557,7 +557,7 @@ static const struct dce_i2c_mask i2c_masks = {
 		I2C_COMMON_MASK_SH_LIST_DCE_COMMON_BASE(_MASK)
 };
 
-struct dce_i2c_hw *dce60_i2c_hw_create(
+static struct dce_i2c_hw *dce60_i2c_hw_create(
 	struct dc_context *ctx,
 	uint32_t inst)
 {
@@ -573,7 +573,7 @@ struct dce_i2c_hw *dce60_i2c_hw_create(
 	return dce_i2c_hw;
 }
 
-struct dce_i2c_sw *dce60_i2c_sw_create(
+static struct dce_i2c_sw *dce60_i2c_sw_create(
 	struct dc_context *ctx)
 {
 	struct dce_i2c_sw *dce_i2c_sw =
@@ -707,7 +707,7 @@ static const struct encoder_feature_support link_enc_feature = {
 		.flags.bits.IS_TPS3_CAPABLE = true
 };
 
-struct link_encoder *dce60_link_encoder_create(
+static struct link_encoder *dce60_link_encoder_create(
 	const struct encoder_init_data *enc_init_data)
 {
 	struct dce110_link_encoder *enc110 =
@@ -746,7 +746,7 @@ static struct panel_cntl *dce60_panel_cntl_create(const struct panel_cntl_init_d
 	return &panel_cntl->base;
 }
 
-struct clock_source *dce60_clock_source_create(
+static struct clock_source *dce60_clock_source_create(
 	struct dc_context *ctx,
 	struct dc_bios *bios,
 	enum clock_source_id id,
@@ -770,7 +770,7 @@ struct clock_source *dce60_clock_source_create(
 	return NULL;
 }
 
-void dce60_clock_source_destroy(struct clock_source **clk_src)
+static void dce60_clock_source_destroy(struct clock_source **clk_src)
 {
 	kfree(TO_DCE110_CLK_SRC(*clk_src));
 	*clk_src = NULL;
@@ -860,7 +860,7 @@ static void dce60_resource_destruct(struct dce110_resource_pool *pool)
 	}
 }
 
-bool dce60_validate_bandwidth(
+static bool dce60_validate_bandwidth(
 	struct dc *dc,
 	struct dc_state *context,
 	bool fast_validate)
@@ -905,7 +905,7 @@ static bool dce60_validate_surface_sets(
 	return true;
 }
 
-enum dc_status dce60_validate_global(
+static enum dc_status dce60_validate_global(
 		struct dc *dc,
 		struct dc_state *context)
 {