[ARM] Add linux/compiler.h includes where required

atomic.h, bitops.h and mmu_context.h are using likely/unlikely.
thread_info.h uses __attribute_const__.  Hence these files require
linux/compiler.h to be included.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/include/asm-arm/bitops.h b/include/asm-arm/bitops.h
index e007dd9..7399d43 100644
--- a/include/asm-arm/bitops.h
+++ b/include/asm-arm/bitops.h
@@ -19,6 +19,7 @@
 
 #ifdef __KERNEL__
 
+#include <linux/compiler.h>
 #include <asm/system.h>
 
 #define smp_mb__before_clear_bit()	mb()