The bias for the gyroscope is not used correctly. The sensor bias
needs to be used in calculation of the 'sensivity' instead of being
an offset.

In practice this has little input on the values as the bias values
tends to be small (+/- 20).
Signed-off-by: Roderick Colenbrander <roderick.colenbrander@sony.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>