axs_nand - add driver for NAND controller used on Synopsys AXS dev boards

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
axs10x: add description of NAND controller to device tree

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
ARC: [axs101] enable built-in NAND controller

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>