media: i2c: set lt6911uxe's reset_gpio to GPIOD_OUT_LOW

reset_gpio needs to be an output and set to GPIOD_OUT_LOW, to ensure
lt6911uxe is in reset state during probe.

This issue was found on the onboard lt6911uxe, where the reset_pin was
not reset, causing the lt6911uxe to fail to probe.

Fixes: e49563c3 ("media: i2c: add lt6911uxe hdmi bridge driver")
Cc: stable@vger.kernel.org
Signed-off-by: Dongcheng Yan <dongcheng.yan@intel.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>