media: rzg2l-cru: fix a test for timeout

The test for if the loop timed out is wrong and Smatch complains:

    drivers/media/platform/renesas/rzg2l-cru/rzg2l-csi2.c:411 rzg2l_csi2_mipi_link_disable()
    warn: should this be 'timeout == -1'

Let's change it to a preop loop instead of a post op loop.

Fixes: 51e8415e ("media: platform: Add Renesas RZ/G2L MIPI CSI-2 receiver driver")
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>