busybox: add mdev patch for 1.21.0

--- busybox-1.21.0/util-linux/mdev.c

+++ busybox-1.21.0-mdev/util-linux/mdev.c

@@ -661,6 +661,8 @@ static void make_device(char *device_nam

 			if (mknod(node_name, rule->mode | type, makedev(major, minor)) && errno != EEXIST)

 				bb_perror_msg("can't create '%s'", node_name);

 			if (ENABLE_FEATURE_MDEV_CONF) {

+				if (G.verbose)

+					bb_error_msg("chmod: %o chown: %u:%u", rule->mode, rule->ugid.uid, rule->ugid.gid);

 				chmod(node_name, rule->mode);

 				chown(node_name, rule->ugid.uid, rule->ugid.gid);

 			}

@@ -813,6 +815,7 @@ static void load_firmware(const char *fi

 		full_write(loading_fd, "-1", 2);

  out:

+	xchdir("/dev");

 	if (ENABLE_FEATURE_CLEAN_UP) {

 		close(firmware_fd);

 		close(loading_fd);

@@ -919,11 +922,13 @@ int mdev_main(int argc UNUSED_PARAM, cha

 		}

 		{

-			int logfd = open("/dev/mdev.log", O_WRONLY | O_APPEND);

+			int logfd = open("mdev.log", O_WRONLY | O_APPEND);

 			if (logfd >= 0) {

 				xmove_fd(logfd, STDERR_FILENO);

 				G.verbose = 1;

-				bb_error_msg("seq: %s action: %s", seq, action);

+				if (seq)

+					applet_name = xasprintf("%s[%s]", applet_name, seq);

+				bb_error_msg("action: %s", action);

 			}

 		}