Since 4.19 upstream kernel provides generic SPI-NAND
framework and vendor specific drivers.
Since only users of MT29F are 2 boards with Winbond
W25N01GV SPI-NAND for which support has been backported
from 4.20 we can drop the ever stuck in staging MT29F
driver and instead use the upstream driver.
Signed-off-by: Robert Marko <robimarko@gmail.com>
Signed-off-by: Christian Lamparter <chunkeey@gmail.com> [squashed]