x86: When cleaning MTRRs, do not fold WP into UC

The current MTRR code treats WP as a form of UC.  This really isn't
desirable behaviour, except possibly in the case of severe MTRR
shortage.  Disable this, to allow legitimate uses of WP to remain
unmolested.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>

arch/x86/kernel/cpu/mtrr/cleanup.c

@@ -689,8 +689,6 @@ static int __init mtrr_need_cleanup(void)
 			continue;
 		if (!size)
 			type = MTRR_NUM_TYPES;
-		if (type == MTRR_TYPE_WRPROT)
-			type = MTRR_TYPE_UNCACHABLE;
 		num[type]++;
 	}