compiler-gcc: remove attribute support check for `__no_sanitize_thread__`

The attribute was added in GCC 5.1, which matches the minimum GCC version
supported by the kernel.

Therefore, remove the check.

Link: https://godbolt.org/z/vbxKejxbx
Link: https://lkml.kernel.org/r/20221021115956.9947-3-ojeda@kernel.org


Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Acked-by: Marco Elver <elver@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Li <ashimida@linux.alibaba.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>