vidioc_int_g_ifparm returns platform-specific information about the
interface settings used by the sensor. Support for [gs]_ext_clk has
been removed.

Fix indentation and remove useless & characters.

Remove experiment for typechecking slave callback function arguments.
Signed-off-by: Sakari Ailus <sakari.ailus@nokia.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>