mtd: nand: add NAND_NEED_SCRAMBLING flag to the H27UCG8T2ATR-BC definition

The H27UCG8T2ATR-BC requires an external data scrambler. Reflect this
constraint in the nand_flash_ids definition.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>