lib: rsa: Add debug message on algo mismatch

Currently we fail silently if there is an algorithm mismatch. To help
distinguish this failure condition.

Signed-off-by: Sean Anderson <sean.anderson@seco.com>
diff --git a/lib/rsa/rsa-verify.c b/lib/rsa/rsa-verify.c
index e34d329..aee76f4 100644
--- a/lib/rsa/rsa-verify.c
+++ b/lib/rsa/rsa-verify.c
@@ -447,8 +447,11 @@
 	}
 
 	algo = fdt_getprop(blob, node, "algo", NULL);
-	if (strcmp(info->name, algo))
+	if (strcmp(info->name, algo)) {
+		debug("%s: Wrong algo: have %s, expected %s", __func__,
+		      info->name, algo);
 		return -EFAULT;
+	}
 
 	prop.num_bits = fdtdec_get_int(blob, node, "rsa,num-bits", 0);