drm/dsc: fix drm_edp_dsc_sink_output_bpp() DPCD high byte usage

The operator precedence between << and & is wrong, leading to the high
byte being completely ignored. For example, with the 6.4 format, 32
becomes 0 and 24 becomes 8. Fix it, and remove the slightly confusing
and unnecessary DP_DSC_MAX_BITS_PER_PIXEL_HI_SHIFT macro while at it.

Fixes: 0575650 ("drm/dp: DRM DP helper/macros to get DP sink DSC parameters")
Cc: Stanislav Lisovskiy <[email protected]>
Cc: Manasi Navare <[email protected]>
Cc: Anusha Srivatsa <[email protected]>
Cc: <[email protected]> # v5.0+
Signed-off-by: Jani Nikula <[email protected]>
Reviewed-by: Ankit Nautiyal <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

Author: jnikula

include/drm/display/drm_dp.h

@@ -286,7 +286,6 @@
 
 #define DP_DSC_MAX_BITS_PER_PIXEL_HI        0x068   /* eDP 1.4 */
 # define DP_DSC_MAX_BITS_PER_PIXEL_HI_MASK  (0x3 << 0)
-# define DP_DSC_MAX_BITS_PER_PIXEL_HI_SHIFT 8
 # define DP_DSC_MAX_BPP_DELTA_VERSION_MASK  0x06
 # define DP_DSC_MAX_BPP_DELTA_AVAILABILITY  0x08
 

include/drm/display/drm_dp_helper.h

@@ -181,9 +181,8 @@ static inline u16
 drm_edp_dsc_sink_output_bpp(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE])
 {
 	return dsc_dpcd[DP_DSC_MAX_BITS_PER_PIXEL_LOW - DP_DSC_SUPPORT] |
-		(dsc_dpcd[DP_DSC_MAX_BITS_PER_PIXEL_HI - DP_DSC_SUPPORT] &
-		 DP_DSC_MAX_BITS_PER_PIXEL_HI_MASK <<
-		 DP_DSC_MAX_BITS_PER_PIXEL_HI_SHIFT);
+		((dsc_dpcd[DP_DSC_MAX_BITS_PER_PIXEL_HI - DP_DSC_SUPPORT] &
+		  DP_DSC_MAX_BITS_PER_PIXEL_HI_MASK) << 8);
 }
 
 static inline u32