media: staging: media: imx: initialize hs_settle to avoid warning

Initialize hs_settle to 0 to avoid this compiler warning:

imx8mq-mipi-csi2.c: In function 'imx8mq_mipi_csi_start_stream.part.0':
imx8mq-mipi-csi2.c:91:55: warning: 'hs_settle' may be used uninitialized [-Wmaybe-uninitialized]
   91 | #define GPR_CSI2_1_S_PRG_RXHS_SETTLE(x) (((x) & 0x3f) << 2)
      |                                                       ^~
imx8mq-mipi-csi2.c:357:13: note: 'hs_settle' was declared here
  357 |         u32 hs_settle;
      |             ^~~~~~~~~

It's a false positive, but it is too complicated for the compiler to detect that.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Reviewed-by: Martin Kepplinger <martink@posteo.de>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>