Replace (1 << ...) with BIT().

CC: Alessandro Zummo <a.zummo@towertech.it>
CC: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Link: https://lore.kernel.org/r/20191218082553.3309554-1-iwamatsu@nigauri.orgSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>