lib: bitmap: micro-optimize bitmap_allocate_region

__reg_op(..., REG_OP_ALLOC) always returns 0, so we might as well use that
and save an instruction.
Signed-off-by: NRasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

lib/bitmap.c

@@ -1154,8 +1154,7 @@ int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order)
 {
 	if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
 		return -EBUSY;
-	__reg_op(bitmap, pos, order, REG_OP_ALLOC);
-	return 0;
+	return __reg_op(bitmap, pos, order, REG_OP_ALLOC);
 }
 EXPORT_SYMBOL(bitmap_allocate_region);