busybox: reduce number of mkdir calls in inittab

The default busybox inittab does two separate mkdir calls
to create /dev/pts and /dev/shm. Reduce this to call mkdir
only once for both directories.

Signed-off-by: Florian La Roche <F.LaRoche@pilz.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit 13dbe73782c3555b382ea8ebd9cda34ac9ef5744)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/busybox/inittab

@@ -16,8 +16,7 @@
 # Startup the system
 ::sysinit:/bin/mount -t proc proc /proc
 ::sysinit:/bin/mount -o remount,rw /
-::sysinit:/bin/mkdir -p /dev/pts
-::sysinit:/bin/mkdir -p /dev/shm
+::sysinit:/bin/mkdir -p /dev/pts /dev/shm
 ::sysinit:/bin/mount -a
 ::sysinit:/bin/hostname -F /etc/hostname
 # now run any rc scripts