bits: add comments and newlines to #if, #else and #endif directives

This is a preparation for the upcoming GENMASK_U*() and BIT_U*()
changes. After introducing those new macros, there will be a lot of
scrolling between the #if, #else and #endif.

Add a comment to the #else and #endif preprocessor macros to help keep
track of which context we are in. Also, add new lines to better
visually separate the non-asm and asm sections.

Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Yury Norov <yury.norov@gmail.com>

Author: vincent-mailhol

include/linux/bits.h

@@ -19,16 +19,21 @@
  * GENMASK_ULL(39, 21) gives us the 64bit vector 0x000000ffffe00000.
  */
 #if !defined(__ASSEMBLY__)
+
 #include <linux/build_bug.h>
 #include <linux/compiler.h>
+
 #define GENMASK_INPUT_CHECK(h, l) BUILD_BUG_ON_ZERO(const_true((l) > (h)))
-#else
+
+#else /* defined(__ASSEMBLY__) */
+
 /*
  * BUILD_BUG_ON_ZERO is not available in h files included from asm files,
  * disable the input check if that is the case.
  */
 #define GENMASK_INPUT_CHECK(h, l) 0
-#endif
+
+#endif /* !defined(__ASSEMBLY__) */
 
 #define GENMASK(h, l) \
 	(GENMASK_INPUT_CHECK(h, l) + __GENMASK(h, l))