drm/i915: Shrink {icl_mg,tgl_dkl}_phy_ddi_buf_trans

All the values we have in {icl_mg,tgl_dkl}_phy_ddi_buf_trans
fit into u8. Shrink the types accordingly.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211006204937.30774-3-ville.syrjala@linux.intel.comReviewed-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/display/intel_ddi_buf_trans.h

@@ -34,15 +34,15 @@ struct icl_ddi_buf_trans {
 };
 
 struct icl_mg_phy_ddi_buf_trans {
-	u32 cri_txdeemph_override_11_6;
-	u32 cri_txdeemph_override_5_0;
-	u32 cri_txdeemph_override_17_12;
+	u8 cri_txdeemph_override_11_6;
+	u8 cri_txdeemph_override_5_0;
+	u8 cri_txdeemph_override_17_12;
 };
 
 struct tgl_dkl_phy_ddi_buf_trans {
-	u32 vswing;
-	u32 preshoot;
-	u32 de_emphasis;
+	u8 vswing;
+	u8 preshoot;
+	u8 de_emphasis;
 };
 
 struct dg2_snps_phy_buf_trans {