drm/radeon: Add new callback that exposes vddc

This patch adds a callback for reporting vddc, to the dpm field of the radeon_asic structure.
Signed-off-by: NSandeep Raghuraman <sandy.8925@gmail.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/radeon.h

@@ -1992,6 +1992,7 @@ struct radeon_asic {
 		int (*get_fan_speed_percent)(struct radeon_device *rdev, u32 *speed);
 		u32 (*get_current_sclk)(struct radeon_device *rdev);
 		u32 (*get_current_mclk)(struct radeon_device *rdev);
+		u16 (*get_current_vddc)(struct radeon_device *rdev);
 	} dpm;
 	/* pageflipping */
 	struct {