iio: proximity: rfd77402: Fix completion race condition in IRQ mode

iio: proximity: rfd77402: Fix completion race condition in IRQ mode

In IRQ mode, the completion was being reinitialized after the
measurement command had already been sent to the hardware. This
created a race condition where the IRQ handler could call complete()
before reinit_completion() was executed. Consequently,
wait_for_completion_timeout() would fail to see the signal and wait
until it timed out.

Move reinit_completion() to occur before the measurement command is
triggered to ensure the synchronization primitive is ready to
capture the interrupt.

Fixes: dc81be96a73a ("iio: proximity: rfd77402: Add interrupt handling support")
Signed-off-by: Felix Gu <ustc.gu@gmail.com>
Reviewed-by: Shrikant Raskar <raskar.shree97@gmail.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>