staging:iio:mag:hmc5843 fix incorrect endianness of channel as a result of missuse...

This driver sets the shift value equal to IIO_BE (or 1) rather than setting
that to 0 and specificying the endianness.  This means the channel type is
missreported as
[be|le]:u16/16>>1 where the be|le is dependent on the cpu native endianness,
rather than
be:u16/16>>0 resulting in any userspace code using this information, miss
converting the channel and generating thoroughly trashed data.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: stable@vger.kernel.org