Allow space in BOARD_*_SIZE variables for dynamic partitions

Allow instances like:
BOARD_SUPER_PARTITION_SIZE := 4294967296 # 4GiB

Test: add trailing space to BOARD_SUPER_PARTITION_SIZE,
BOARD_(group)_SIZE, BOARD_*IMAGE_PARTITION_RESERVED_SIZE,
BOARD_SUPER_PARTITION_(device)_DEVICE_SIZE, build passes.

Fixes: 120042457
Change-Id: Ib7244e3fd2f782657c84cdb74e601ac96176571d