greybus: reorder greybus_svc_in() arguments

The two functions greybus_svc_in() and greybus_cport_in() do
very similar things, but their arguments are in a different order.
Move the greybus_host_device structure argument for greybus_svc_in()
to be first so the functions' prototypes are better aligned.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>