lib: rsa: rsa-verify: also check that padding is not NULL

This commit adds a check on the padding in the function rsa_verify_key
to avoid using a NULL pointer.

Signed-off-by: Philippe Reynes <philippe.reynes@softathome.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/lib/rsa/rsa-verify.c b/lib/rsa/rsa-verify.c
index 600c93a..83f7564 100644
--- a/lib/rsa/rsa-verify.c
+++ b/lib/rsa/rsa-verify.c
@@ -340,7 +340,7 @@
 	struct padding_algo *padding = info->padding;
 	int hash_len;
 
-	if (!prop || !sig || !hash || !checksum)
+	if (!prop || !sig || !hash || !checksum || !padding)
 		return -EIO;
 
 	if (sig_len != (prop->num_bits / 8)) {