drm/radeon/dpm: fix incompatible casting on big endian

We use u16 for voltage values throughout the driver so switch
the table values to a u16 as well.  Fixes an incompatible
cast error in ci_patch_clock_voltage_limits_with_vddc_leakage()
picked up by coverity.
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/radeon.h

@@ -1272,8 +1272,8 @@ struct radeon_blacklist_clocks
 struct radeon_clock_and_voltage_limits {
 	u32 sclk;
 	u32 mclk;
-	u32 vddc;
-	u32 vddci;
+	u16 vddc;
+	u16 vddci;
 };
 
 struct radeon_clock_array {