drm/amd/pm/powerplay/hwmgr/hwmgr: Move prototype into shared header

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

 drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr/vega10_hwmgr.c:5474:5: warning: no previous prototype for ‘vega10_hwmgr_init’ [-Wmissing-prototypes]

Cc: Evan Quan <evan.quan@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: 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/pm/powerplay/hwmgr/hwmgr.c

@@ -33,6 +33,7 @@
 #include "ppsmc.h"
 #include "amd_acpi.h"
 #include "pp_psm.h"
+#include "vega10_hwmgr.h"
 
 extern const struct pp_smumgr_func ci_smu_funcs;
 extern const struct pp_smumgr_func smu8_smu_funcs;
@@ -46,7 +47,6 @@ extern const struct pp_smumgr_func vega12_smu_funcs;
 extern const struct pp_smumgr_func smu10_smu_funcs;
 extern const struct pp_smumgr_func vega20_smu_funcs;
 
-extern int vega10_hwmgr_init(struct pp_hwmgr *hwmgr);
 extern int smu10_init_function_pointers(struct pp_hwmgr *hwmgr);
 
 static int polaris_set_asic_special_caps(struct pp_hwmgr *hwmgr);

drivers/gpu/drm/amd/pm/powerplay/hwmgr/vega10_hwmgr.h

@@ -442,5 +442,6 @@ int vega10_update_uvd_dpm(struct pp_hwmgr *hwmgr, bool bgate);
 int vega10_update_samu_dpm(struct pp_hwmgr *hwmgr, bool bgate);
 int vega10_update_acp_dpm(struct pp_hwmgr *hwmgr, bool bgate);
 int vega10_enable_disable_vce_dpm(struct pp_hwmgr *hwmgr, bool enable);
+int vega10_hwmgr_init(struct pp_hwmgr *hwmgr);
 
 #endif /* _VEGA10_HWMGR_H_ */