ARM: provide common method to clear bits in CPU control register

Several places open-code this manipulation, let's consolidate this.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 2a77ba8..94332b1 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -23,6 +23,7 @@
 #include <linux/dma-contiguous.h>
 #include <linux/sizes.h>
 
+#include <asm/cp15.h>
 #include <asm/mach-types.h>
 #include <asm/memblock.h>
 #include <asm/prom.h>
@@ -36,6 +37,15 @@
 
 #include "mm.h"
 
+#ifdef CONFIG_CPU_CP15_MMU
+unsigned long __init __clear_cr(unsigned long mask)
+{
+	cr_no_alignment = cr_no_alignment & ~mask;
+	cr_alignment = cr_alignment & ~mask;
+	return cr_alignment;
+}
+#endif
+
 static phys_addr_t phys_initrd_start __initdata = 0;
 static unsigned long phys_initrd_size __initdata = 0;