rsa: add a structure for the padding

The rsa signature use a padding algorithm. By default, we use the
padding pkcs-1.5. In order to add some new padding algorithm, we
add a padding framework to manage several padding algorithm.
The choice of the padding is done in the file .its.

Signed-off-by: Philippe Reynes <philippe.reynes@softathome.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/image-host.c b/tools/image-host.c
index 09e4f47..88b3295 100644
--- a/tools/image-host.c
+++ b/tools/image-host.c
@@ -157,6 +157,7 @@
 {
 	const char *node_name;
 	char *algo_name;
+	const char *padding_name;
 
 	node_name = fit_get_name(fit, noffset, NULL);
 	if (fit_image_hash_get_algo(fit, noffset, &algo_name)) {
@@ -165,6 +166,8 @@
 		return -1;
 	}
 
+	padding_name = fdt_getprop(fit, noffset, "padding", NULL);
+
 	memset(info, '\0', sizeof(*info));
 	info->keydir = keydir;
 	info->keyname = fdt_getprop(fit, noffset, "key-name-hint", NULL);
@@ -173,6 +176,7 @@
 	info->name = strdup(algo_name);
 	info->checksum = image_get_checksum_algo(algo_name);
 	info->crypto = image_get_crypto_algo(algo_name);
+	info->padding = image_get_padding_algo(padding_name);
 	info->require_keys = require_keys;
 	info->engine_id = engine_id;
 	if (!info->checksum || !info->crypto) {