mtd: rawnand: atmel: add sam9x60 nand controller support

The sam9x60 board defines the CCFG_EBICSA register under SFR,
and not as a MATRIX register, as previous boards do.

NAND Flash I/Os are connected to D16–D23, thus
SFR_CCFG_EBICSA.NFD0_ON_D16 is set to 1.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>