greybus: es1/2: Lets start using svc protocol

All bits and pieces are in place now. Lets start using svc protocol
instead of stuff present in ap.c.

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>