md/raid6: implement recovery using ARM NEON intrinsics

Provide a NEON accelerated implementation of the recovery algorithm,
which supersedes the default byte-by-byte one.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

lib/raid6/algos.c

@@ -112,6 +112,9 @@ const struct raid6_recov_calls *const raid6_recov_algos[] = {
 #endif
 #ifdef CONFIG_S390
 	&raid6_recov_s390xc,
+#endif
+#if defined(CONFIG_KERNEL_MODE_NEON)
+	&raid6_recov_neon,
 #endif
 	&raid6_recov_intx1,
 	NULL