mkefidisk.sh: mount images as read-only
Mount the hddimg and rootfs.img as read-only when creating the bootable
image on the medium. Otherwise, the md5 checksum values of the hddimg will
be altered. As this changed checksum value might cause issue for users
whom would reuse the hddimg.
(From OE-Core rev:
a1391c8a603f0ed972ee0bcc8c74999f5f43be43)
Signed-off-by: Raymond Tan <raymond.tan@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Armin Kuster <akuster@mvista.com>
