Avoid divide in IS_ALIGN

I was happy to discover the brand new IS_ALIGN macro and quickly used it in
my code.  To my dismay I found that the generated code used division to
perform the test.

This patch fixes it by changing the % test to an &.  This avoids the
division.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

include/linux/kernel.h

@@ -35,7 +35,7 @@ extern const char linux_proc_banner[];
 #define ALIGN(x,a)		__ALIGN_MASK(x,(typeof(x))(a)-1)
 #define __ALIGN_MASK(x,mask)	(((x)+(mask))&~(mask))
 #define PTR_ALIGN(p, a)		((typeof(p))ALIGN((unsigned long)(p), (a)))
-#define IS_ALIGNED(x,a)		(((x) % ((typeof(x))(a))) == 0)
+#define IS_ALIGNED(x, a)		(((x) & ((typeof(x))(a) - 1)) == 0)
 
 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))