mtd: nand: kill NAND_NO_READRDY

According to its documentation, the NAND_NO_READRDY option is always used
when autoincrement is not supported. Autoincrement support was recently
dropped, so we can drop this options as well (defaulting to "no read ready
check").

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>