spi: cadence-quadspi: Prevent lost complete() call during indirect read

spi: cadence-quadspi: Prevent lost complete() call during indirect read

A race condition exists between the read loop and IRQ `complete()` call.
An interrupt could call the complete() between the inner loop and
reinit_completion(), potentially losing the completion event and causing
an unnecessary timeout. Moving reinit_completion() before the loop
prevents this. A premature signal will only result in a spurious wakeup
and another wait cycle, which is preferable to waiting for a timeout.

Signed-off-by: Mateusz Litwin <mateusz.litwin@nokia.com>
Link: https://patch.msgid.link/20251218-cqspi_indirect_read_improve-v2-1-396079972f2a@nokia.com
Signed-off-by: Mark Brown <broonie@kernel.org>