mtd: davinci-nand: disable subpage write for keystone-nand

Sub page write doesn't work because of hw issue in controller found on
Keystone SOCs. AEMIF controller is also used on DaVinci SOCs which
don't seems to have any issue. So add "ti,keysone-nand" compatible
to nand driver in order to set NAND_NO_SUBPAGE_WRITE option.

Cc: Warner Losh <imp@bsdimp.com>
Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>