ARM: includecheck fix: atomic.h

fix the following 'make includecheck' warning:

  arch/arm/include/asm/atomic.h: asm/system.h is included more than once.

Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/include/asm/atomic.h b/arch/arm/include/asm/atomic.h
index 9e07fe5..9ed2377 100644
--- a/arch/arm/include/asm/atomic.h
+++ b/arch/arm/include/asm/atomic.h
@@ -159,8 +159,6 @@
 
 #else /* ARM_ARCH_6 */
 
-#include <asm/system.h>
-
 #ifdef CONFIG_SMP
 #error SMP not supported on pre-ARMv6 CPUs
 #endif