intel/haswell: Remove useless MTRR clear

At this state, variable MTRRs are disabled. We overwrite this MTRR entry
before they are re-enabled.

Change-Id: Ieedf90f65514d848905626e75be496e08f710d91
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/15794
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/cpu/intel/haswell/cache_as_ram.inc

@@ -209,14 +209,6 @@ before_romstage:
 	andl    $~1, %eax
 	wrmsr
 
-	/* Clear MTRR that was used to cache MRC */
-	xorl	%eax, %eax
-	xorl	%edx, %edx
-	movl	$MTRR_PHYS_BASE(2), %ecx
-	wrmsr
-	movl	$MTRR_PHYS_MASK(2), %ecx
-	wrmsr
-
 	post_code(0x33)
 
 	/* Enable cache. */