i2c: i801: use BIT() macro for bits definition

i801 mixes hexadecimal and decimal values for defining bits. However,
we have a nice BIT() macro for this exact purpose.

No functional changes, cleanup only.

Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>