[media] V4L: Drop bus_type check in v4l2-async match functions

These match_* functions are internal callbacks and are always
invoked only after checking asd->bus_type. So drop redundant
checks in match_i2c() and match_platform() functions.
Acked-and-tested-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>