x86: update AS_* macros to binutils >=2.23, supporting ADX and AVX2

Now that the kernel specifies binutils 2.23 as the minimum version, we
can remove ifdefs for AVX2 and ADX throughout.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

arch/x86/crypto/chacha_glue.c

@@ -79,8 +79,7 @@ static void chacha_dosimd(u32 *state, u8 *dst, const u8 *src,
 		}
 	}
 
-	if (IS_ENABLED(CONFIG_AS_AVX2) &&
-	    static_branch_likely(&chacha_use_avx2)) {
+	if (static_branch_likely(&chacha_use_avx2)) {
 		while (bytes >= CHACHA_BLOCK_SIZE * 8) {
 			chacha_8block_xor_avx2(state, dst, src, bytes, nrounds);
 			bytes -= CHACHA_BLOCK_SIZE * 8;
@@ -288,8 +287,7 @@ static int __init chacha_simd_mod_init(void)
 
 	static_branch_enable(&chacha_use_simd);
 
-	if (IS_ENABLED(CONFIG_AS_AVX2) &&
-	    boot_cpu_has(X86_FEATURE_AVX) &&
+	if (boot_cpu_has(X86_FEATURE_AVX) &&
 	    boot_cpu_has(X86_FEATURE_AVX2) &&
 	    cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, NULL)) {
 		static_branch_enable(&chacha_use_avx2);