staging: exfat: remove return and error return via a goto

The return statement is incorrect, the error exit should be by
assigning ret with the error code and exiting via label out.
Thanks to Valdis Klētnieks for correcting my original fix.

Addresses-Coverity: ("Structurally dead code")
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20190902094052.28029-1-colin.king@canonical.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/exfat/exfat_super.c

@@ -670,7 +670,7 @@ static int ffsLookupFile(struct inode *inode, char *path, struct file_id_t *fid)
 	dentry = p_fs->fs_func->find_dir_entry(sb, &dir, &uni_name, num_entries,
 					       &dos_name, TYPE_ALL);
 	if (dentry < -1) {
-		return FFS_NOTFOUND;
+		ret = FFS_NOTFOUND;
 		goto out;
 	}