drm/tegra: sor: Use DP link training helpers

Make use of the DP link training helpers to implement full and fast link
training. While at it, refactor some of the code and remove various code
sequences that are not necessary.

Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/drm/tegra/sor.h

@@ -283,10 +283,12 @@
 #define  SOR_DP_PADCTL_CM_TXD_2		(1 << 6)
 #define  SOR_DP_PADCTL_CM_TXD_1		(1 << 5)
 #define  SOR_DP_PADCTL_CM_TXD_0		(1 << 4)
+#define  SOR_DP_PADCTL_CM_TXD(x)	(1 << (4 + (x)))
 #define  SOR_DP_PADCTL_PD_TXD_3		(1 << 3)
 #define  SOR_DP_PADCTL_PD_TXD_0		(1 << 2)
 #define  SOR_DP_PADCTL_PD_TXD_1		(1 << 1)
 #define  SOR_DP_PADCTL_PD_TXD_2		(1 << 0)
+#define  SOR_DP_PADCTL_PD_TXD(x)	(1 << (0 + (x)))
 
 #define SOR_DP_PADCTL1 0x5d