iio:magnetometer:bmc150_magn: replace magic value

Construct the scanmask using its descriptive axis names (as used in
iio_chan_spec) instead of a 'magic' value.

Signed-off-by: Hartmut Knaack <knaack.h@gmx.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
1 file changed