linux/bits.h: simplify GENMASK_INPUT_CHECK()

In GENMASK_INPUT_CHECK(),

  __builtin_choose_expr(__is_constexpr((l) > (h)), (l) > (h), 0)

is the exact expansion of:

  const_true((l) > (h))

Apply const_true() to simplify GENMASK_INPUT_CHECK().

CC: Linus Torvalds <torvalds@linux-foundation.org>
CC: Rasmus Villemoes <linux@rasmusvillemoes.dk>
CC: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Reviewed-by: Yury Norov <yury.norov@gmail.com>,
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: Yury Norov <yury.norov@gmail.com>

Author: vincent-mailhol

include/linux/bits.h

@@ -20,9 +20,8 @@
  */
 #if !defined(__ASSEMBLY__)
 #include <linux/build_bug.h>
-#define GENMASK_INPUT_CHECK(h, l) \
-	(BUILD_BUG_ON_ZERO(__builtin_choose_expr( \
-		__is_constexpr((l) > (h)), (l) > (h), 0)))
+#include <linux/compiler.h>
+#define GENMASK_INPUT_CHECK(h, l) BUILD_BUG_ON_ZERO(const_true((l) > (h)))
 #else
 /*
  * BUILD_BUG_ON_ZERO is not available in h files included from asm files,