Support ARM64EC in the same way as ARM64 in sha256 and sha512

Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/library/sha512.c b/library/sha512.c
index e739af2..23e8745 100644
--- a/library/sha512.c
+++ b/library/sha512.c
@@ -154,7 +154,7 @@
                            NULL, 0);
     return ret == 0 && value != 0;
 }
-#elif defined(_M_ARM64)
+#elif defined(_M_ARM64) || defined(_M_ARM64EC)
 /*
  * As of March 2022, there don't appear to be any PF_ARM_V8_* flags
  * available to pass to IsProcessorFeaturePresent() to check for