wic: account for mmcblk device partition naming
MMC block device partitions are named differently than other block
devices and use the scheme: mmcblk<devnum>p<partnum>, ex: mmcblk0p1,
mmcblk0p2. The current code generates incorrect parition names missing
'p' infix for fstab entries. The patch resolves this problem.
Signed-off-by: Maciej Borzecki <maciej.borzecki@open-rnd.pl>
Signed-off-by: Maciek Borzecki <maciek.borzecki@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
