mtd: rawnand: denali: include <linux/bits.h> instead of <linux/bitops.h>

The reason of including <linux/bitops.h> here is just for BIT() and
GENMASK macros.

Since commit 8bd9cb51 ("locking/atomics, asm-generic: Move some
macros from <linux/bitops.h> to a new <linux/bits.h> file"),
<linux/bits.h> is enough for such compile-time macros.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>