mount.sh: automount cdrom device even if no ID_FS_TYPE available

mount.sh: automount cdrom device even if no ID_FS_TYPE available

This script was modified to check whether $ID_FS_TYPE is empty before
automount, however, for cdrom devices on qemu, the ID_FS_TYPE is not
set, yet the device should be mounted. Otherwise, when booting an iso
image with runqemu, the boot process hangs at 'waiting for removable
media'.

This patch fixes this problem by first checking whether the block device
is a cdrom.

[YOCTO #4487]

(From OE-Core rev: 2df21a3b27543df912a3ce05bef2415fae13cb7c)

Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>