greybus: svc: connection is created only once now

We no longer create a fresh connection on receiving svc-hello message,
but rather update the initial one.

Update 'initial_svc_connection' after the connection is fully
initialized. Look for the partially initialized connection while
removing hd, as hd might be removed before getting svc-hello requests
from svc.

Also update gb_svc_connection_init() to initialize id_map on the first
(and the only) call to connection-init function.

We also can't update connection->bundle->intf->svc, as its a bundle-less
connection. Lets stop updating intf->svc as its not really used.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Perry Hung <perry@leaflabs.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>