media: atomisp: Drop atomisp_get_css_buf_type()

Since continuous mode has been removed, there no longer is the option for
separate capture output + viewfinder output streams at the same time.

So all buffers queued by userspace are now for the normal output stream,
remove atomisp_get_css_buf_type() and always use
IA_CSS_BUFFER_TYPE_OUTPUT_FRAME for buffers queued by userspace.

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