compiler_attributes.h: cleanups for GCC 4.9+

Since
commit 6ec4476 ("Raise gcc version requirement to 4.9")
we no longer support building the kernel with GCC 4.8; drop the
preprocess checks for __GNUC_MINOR__ version. It's implied that if
__GNUC_MAJOR__ is 4, then the only supported version of __GNUC_MINOR__
left is 9.

Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210621231822.2848305-3-ndesaulniers@google.com

include/linux/compiler_attributes.h

@@ -27,16 +27,16 @@
  */
 #ifndef __has_attribute
 # define __has_attribute(x) __GCC4_has_attribute_##x
-# define __GCC4_has_attribute___assume_aligned__      (__GNUC_MINOR__ >= 9)
+# define __GCC4_has_attribute___assume_aligned__      1
 # define __GCC4_has_attribute___copy__                0
 # define __GCC4_has_attribute___designated_init__     0
 # define __GCC4_has_attribute___externally_visible__  1
 # define __GCC4_has_attribute___no_caller_saved_registers__ 0
 # define __GCC4_has_attribute___noclone__             1
 # define __GCC4_has_attribute___no_profile_instrument_function__ 0
 # define __GCC4_has_attribute___nonstring__           0
-# define __GCC4_has_attribute___no_sanitize_address__ (__GNUC_MINOR__ >= 8)
-# define __GCC4_has_attribute___no_sanitize_undefined__ (__GNUC_MINOR__ >= 9)
+# define __GCC4_has_attribute___no_sanitize_address__ 1
+# define __GCC4_has_attribute___no_sanitize_undefined__ 1
 # define __GCC4_has_attribute___fallthrough__         0
 #endif