nand: Sync with Linux v4.1

Update the NAND code to match Linux v4.1.  The previous sync was
from Linux v3.15 in commit 4e67c571.

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>