image: Combine image_sig_algo with image_sign_info

Remove the need to explicitly add SHA/RSA pairings. Invalid SHA/RSA
pairings will still fail on verify operations when the hash length is
longer than the key length.

Follow the same naming scheme "checksum,crytpo" without explicitly
defining the string.

Indirectly adds support for "sha1,rsa4096" signing/verification.

Signed-off-by: Andrew Duda <aduda@meraki.com>
Signed-off-by: aduda <aduda@meraki.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/lib/rsa/rsa-verify.c b/lib/rsa/rsa-verify.c
index 61dc4c2..0d548f8 100644
--- a/lib/rsa/rsa-verify.c
+++ b/lib/rsa/rsa-verify.c
@@ -184,8 +184,7 @@
 	}
 
 	ret = rsa_verify_key(&prop, sig, sig_len, hash,
-			     info->algo->crypto->key_len,
-			     info->algo->checksum);
+			     info->crypto->key_len, info->checksum);
 
 	return ret;
 }
@@ -196,7 +195,7 @@
 {
 	const void *blob = info->fdt_blob;
 	/* Reserve memory for maximum checksum-length */
-	uint8_t hash[info->algo->crypto->key_len];
+	uint8_t hash[info->crypto->key_len];
 	int ndepth, noffset;
 	int sig_node, node;
 	char name[100];
@@ -206,11 +205,10 @@
 	 * Verify that the checksum-length does not exceed the
 	 * rsa-signature-length
 	 */
-	if (info->algo->checksum->checksum_len >
-	    info->algo->crypto->key_len) {
+	if (info->checksum->checksum_len >
+	    info->crypto->key_len) {
 		debug("%s: invlaid checksum-algorithm %s for %s\n",
-		      __func__, info->algo->checksum->name,
-		      info->algo->crypto->name);
+		      __func__, info->checksum->name, info->crypto->name);
 		return -EINVAL;
 	}
 
@@ -221,7 +219,7 @@
 	}
 
 	/* Calculate checksum with checksum-algorithm */
-	ret = info->algo->checksum->calculate(info->algo->checksum->name,
+	ret = info->checksum->calculate(info->checksum->name,
 					region, region_count, hash);
 	if (ret < 0) {
 		debug("%s: Error in checksum calculation\n", __func__);