device-solidrun-cubox: switch partitition_type to msdos

Since pmbootstrap!2426 (merged), pmbootstrap defaults to a gpt partition type, the legacy u-boot on the cubox does not support gpt.

Therefore the deviceinfo was adjusted to return to msdos type partition table.

Tested sucessfully on actual HW with new install

Signed-off-by: Robert Eckelmann longnoserob@postmarketos.org