arm: mvebu: lowlevel.S: Use CR_M from asm/system.h

Replace magic constant 1 when disabling MMU by macro CR_M from include
header file asm/system.h.

Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Marek Behún <kabel@kernel.org>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/arch/arm/mach-mvebu/lowlevel.S b/arch/arm/mach-mvebu/lowlevel.S
index 2491310..b460382 100644
--- a/arch/arm/mach-mvebu/lowlevel.S
+++ b/arch/arm/mach-mvebu/lowlevel.S
@@ -2,6 +2,7 @@
 
 #include <config.h>
 #include <linux/linkage.h>
+#include <asm/system.h>
 
 ENTRY(arch_very_early_init)
 #ifdef CONFIG_ARMADA_38X
@@ -12,7 +13,7 @@
 	 * still locked to cache.
 	 */
 	mrc	p15, 0, r0, c1, c0, 0
-	bic	r0, #1
+	bic	r0, #CR_M
 	mcr	p15, 0, r0, c1, c0, 0
 #endif