x-wic.inc: Rename *DEVICEDATA* to *DEVDATA* for consistency

This makes things cleaner and more consistent when the other partitions
use variables like:
SYSDATA_PARTITION_SIZE
APPDATA_PARTITION_SIZE
etc.

Keep this change consistent on the wic files too.

Signed-off-by: Andrei Gherzan <andrei.gherzan@huawei.com>