NAND: remove NAND_MAX_CHIPS definitions
This change follows the change by Wolfgang Grandegger (commit 6c869637fef),
which allows to remove useless NAND_MAX_CHIPS definitions in board config
files.
Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Cc: Wolfgang Grandegger <wg@grandegger.com>
Cc: Scott Wood <scottwood@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>