Add devm for ioremap to proper cleanup.
Test gpiod_direction_input for failure.
Remove rb91x_nand_release and fix wrong usage.
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Link: https://github.com/openwrt/openwrt/pull/21165
Signed-off-by: Robert Marko <robimarko@gmail.com>