greybus: svc: double the ping delay timeout

Sometimes the ping response comes back _right_ after we timed out, as
the svc got its act together and squeaked out the ack, yet we miss it
and reset the whole bus.  Double the delay to hopefully give the svc a
little more of a chance to fix itself.  Odds are, it's still in trouble,
but we can just hold off resetting it for a bit more...

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>