drm/xe: Don't hardcode GuC's MOCS index in register header

Although PVC is currently the only platform that needs us to program a
GuC register with the index of an uncached MOCS entry, it's likely other
platforms will need this in the future.  Rather than hardcoding PVC's
index into the register header, we should just pull the appropriate
index from gt->mocs.uc_index to future-proof the code.
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://lore.kernel.org/r/20230602235210.1314028-3-matthew.d.roper@intel.comSigned-off-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

drivers/gpu/drm/xe/regs/xe_guc_regs.h

@@ -45,10 +45,7 @@
 #define   GUC_WOPCM_SIZE_LOCKED			REG_BIT(0)
 
 #define GUC_SHIM_CONTROL			XE_REG(0xc064)
-#define   PVC_GUC_MOCS_INDEX_MASK		REG_GENMASK(25, 24)
-#define   PVC_GUC_MOCS_UC_INDEX			1
-#define   PVC_GUC_MOCS_INDEX(index)		REG_FIELD_PREP(PVC_GUC_MOCS_INDEX_MASK, \
-							       index)
+#define   GUC_MOCS_INDEX_MASK			REG_GENMASK(25, 24)
 #define   GUC_SHIM_WC_ENABLE			REG_BIT(21)
 #define   GUC_ENABLE_MIA_CLOCK_GATING		REG_BIT(15)
 #define   GUC_ENABLE_READ_CACHE_FOR_WOPCM_DATA	REG_BIT(10)

drivers/gpu/drm/xe/xe_guc.c

@@ -328,7 +328,7 @@ static void guc_prepare_xfer(struct xe_guc *guc)
 				GUC_ENABLE_MIA_CACHING;
 
 	if (xe->info.platform == XE_PVC)
-		shim_flags |= PVC_GUC_MOCS_INDEX(PVC_GUC_MOCS_UC_INDEX);
+		shim_flags |= REG_FIELD_PREP(GUC_MOCS_INDEX_MASK, gt->mocs.uc_index);
 
 	/* Must program this register before loading the ucode with DMA */
 	xe_mmio_write32(gt, GUC_SHIM_CONTROL, shim_flags);