staging:iio:adc:ad7280a: Fix handing of device address bit reversing.

The bit reversal was wrong for bits 1 and 3 of the 5 bits.
Result is driver failure to probe if you have more than 2 daisy-chained
devices.  Discovered via QEMU based device emulation.

Fixes tag is for when this moved from a macro to a function, but it
was broken before that.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Fixes: 065a7c0b ("Staging: iio: adc: ad7280a.c: Fixed Macro argument reuse")
Reviewed-by: Marcelo Schmitt <marcelo.schmitt1@gmail.com>
Link: https://lore.kernel.org/r/20220206190328.333093-2-jic23@kernel.org