mtd: fsl_elbc_nand: remove unnecessary badblock_pattern

Since the introduction of nand_create_default_bbt_descr() (now known as
nand_create_badblock_pattern()) in

  commit 58373ff0

nand_chip.badblock_pattern will be dynamically calculated to the same
1-byte-length pattern that is required by fsl_elbc_nand. This custom
badblock_pattern is no longer needed, then, and its removal may help
facilitate further nand_bbt.c/nand_base.c cleanup in the future (one
down, many to go?)

Anyway, with nand_bbt.c fixed, this effectively reverts:

  commit 452db272
  [MTD] [NAND] fsl_elbc_nand: fix OOB workability for large page NAND chips

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Cc: Scott Wood <scottwood@freescale.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>