media: platform: sun6i-csi: drop of_match_ptr for ID table

The driver can match only via the DT table so the table should be always
used and the of_match_ptr does not have any sense (this also allows ACPI
matching via PRP0001, even though it might not be relevant here).  This
also fixes !CONFIG_OF error:

  drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.c:401:34: error: ‘sun6i_csi_of_match’ defined but not used [-Werror=unused-const-variable=]

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>