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>
diff --git a/include/linux/raid/pq.h b/include/linux/raid/pq.h
index 30f9453..583cdd3 100644
--- a/include/linux/raid/pq.h
+++ b/include/linux/raid/pq.h
@@ -121,6 +121,7 @@ extern const struct raid6_recov_calls raid6_recov_ssse3;
 extern const struct raid6_recov_calls raid6_recov_avx2;
 extern const struct raid6_recov_calls raid6_recov_avx512;
 extern const struct raid6_recov_calls raid6_recov_s390xc;
+extern const struct raid6_recov_calls raid6_recov_neon;
 
 extern const struct raid6_calls raid6_neonx1;
 extern const struct raid6_calls raid6_neonx2;