drm/amd/display: Add regamma lut write mask to SOC base

Mask and shift values for DCP0_REGAMMA_LUT_WRITE_EN_MASK were missing
from XFM_COMMON_MASK_SH_LIST_SOC_BASE. Add it.
Signed-off-by: Leo (Sunpeng) Li <sunpeng.li@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dce/dce_transform.h

@@ -248,6 +248,7 @@
 	XFM_SF(DCP0_REGAMMA_CNTLA_REGION_0_1, REGAMMA_CNTLA_EXP_REGION1_LUT_OFFSET, mask_sh),\
 	XFM_SF(DCP0_REGAMMA_CNTLA_REGION_0_1, REGAMMA_CNTLA_EXP_REGION1_NUM_SEGMENTS, mask_sh),\
 	XFM_SF(DCP0_REGAMMA_CONTROL, GRPH_REGAMMA_MODE, mask_sh),\
+	XFM_SF(DCP0_REGAMMA_LUT_WRITE_EN_MASK, REGAMMA_LUT_WRITE_EN_MASK, mask_sh),\
 	XFM_SF(SCL0_SCL_MODE, SCL_MODE, mask_sh), \
 	XFM_SF(SCL0_SCL_TAP_CONTROL, SCL_H_NUM_OF_TAPS, mask_sh), \
 	XFM_SF(SCL0_SCL_TAP_CONTROL, SCL_V_NUM_OF_TAPS, mask_sh), \