media: atomisp: Drop atomisp_pipe_check() from atomisp_link_setup()

The media-controller core (__media_entity_setup_link()) already checks
that the pads of the link are not streaming before calling the setup_link()
pad-op so calling atomisp_pipe_check() is not necessary;

and taking isp->mutex inside the setup_link() pad-op leads to a possible
ABBA deadlock vs the media-device graph_mutex which in the case of
the setup_link() pad-op is taken before calling the op, while in other
scenarios the graph_mutex is taken after the isp->mutex.

Reviewed-by: Andy Shevchenko <andy@kernel.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>