mediatek: include 'fitblk' package for subtargets

mediatek: include 'fitblk' package for subtargets

If selected on a per-board base, fitblk doesn't end up in initramfs
images which always only come with the subtarget's default packages.
Hence fitblk needs to be included as a default package of all
subtargets making use of fitblk instead of it being selected for
individual boards.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>