spi: spidev: Fix double unlock in spidev_sync()

This unlocks twice due to a merge issue.

Fixes: 35bba23e ("Merge remote-tracking branch 'spi/for-6.2' into spi-6.2")
Signed-off-by: Dan Carpenter <error27@gmail.com>
Link: https://lore.kernel.org/r/Y+ETCk7XKfAy8yWQ@kili


Signed-off-by: Mark Brown <broonie@kernel.org>