Address a few compiler warnings

Change-Id: I6e063fba8d58c8c53da6bca6292c84e3392aee50
diff --git a/partition.cpp b/partition.cpp
index 0651541..6a7ad71 100644
--- a/partition.cpp
+++ b/partition.cpp
@@ -1386,7 +1386,7 @@
 	if (Is_Decrypted) {
 		if (!UnMount(true))
 			return false;
-		if (delete_crypto_blk_dev("userdata") != 0) {
+		if (delete_crypto_blk_dev((char*)("userdata")) != 0) {
 			LOGERR("Error deleting crypto block device, continuing anyway.\n");
 		}
 	}