The v4l2_subdev_get_try_format() function is only defined if the
VIDEO_V4L2_SUBDEV_API Kconfig option is enabled. Builds configured
without that symbol fails with:

drivers/media/i2c/mt9v111.c:801:10: error: implicit declaration of function
'v4l2_subdev_get_try_format';

Fix this by protecting the function call by testing for the right symbol.

media: mt9v111: fix random build errors

Fix the internal check for it to do the right thing if the
subdev API is not built.

Fixes: aab7ed1c ("media: i2c: Add driver for Aptina MT9V111")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>