cpu/x86: Define MTRR_CAP_PRMRR

Followups will remove remaining cases of PRMRR_SUPPORTED and
SMRR_SUPPORTED in the tree.

Change-Id: I7f8c7d98f5e83a45cc0787c245cdcaf8fab176d5
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/42358
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/soc/intel/skylake/cpu.c

@@ -355,6 +355,6 @@ int soc_skip_ucode_update(u32 current_patch_id, u32 new_patch_id)
 	if (msr2.lo && (current_patch_id == new_patch_id - 1))
 		return 0;
 	else
-		return (msr1.lo & PRMRR_SUPPORTED) &&
+		return (msr1.lo & MTRR_CAP_PRMRR) &&
 			(current_patch_id == new_patch_id - 1);
 }