media: i2c: imx: Add note to prevent buggy code re-use

Multiple Sony IMX sensor drivers have mixed up logical and line level
for XCLR signal.  They call it a reset signal (it indeed behaves like
that), but drivers assert the reset to operate which is clearly
incorrect and relies on incorrect DTS.

People in discussions copy existing poor code and claim they can repeat
same mistake, so add a note to prevent that.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>