greybus: endo: pass endo_id to gb_endo_create()

We are going to want to defer creating the endo until we receive a
probe operation from the SVC, which will supply the endo id.  Change
gb_endo_create() so it passes the endo_id value as an argument.

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