Update the NAND code to match Linux v4.1. The previous sync was
from Linux v3.15 in commit 4e67c57125.
CONFIG_SYS_NAND_RESET_CNT is removed, as the upstream Linux code now
has its own timeout. Plus, CONFIG_SYS_NAND_RESET_CNT was undocumented
and not selected by any board.
Signed-off-by: Scott Wood <scottwood@freescale.com>