mtd: rawnand: meson: add missing ENOMEM check in meson_nfc_read_buf()

kzalloc() can return NULL if memory could not be allocated. Check the
return value of the kzalloc() call in meson_nfc_read_buf() to make it
consistent with other memory allocations within the meson_nand driver.

Fixes: 8fae856c ("mtd: rawnand: meson: add support for Amlogic NAND flash controller")
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Acked-by: Liang Yang <liang.yang@amlogic.com>
Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>