VRLSB_SHIFT is a non-sense, the actual shift depends on the sensor
type (fans need 4, other sensors need 6). Get rid of it to prevent
any confusion. Also get rid of the useless masking, the meaningful
bits are always the MSb so there's nothing to mask out after
shifting.
Signed-off-by: NJean Delvare <khali@linux-fr.org>