greybus: greybus_protocols.h Add SVC_TIMESYNC_WAKE_PINS_ACQUIRE/RELEASE

Its necessary to establish an initial state on the wake-detect lines before
enabling timesync on APB/GPB in order to ensure all GPIO edge-transitions are
correctly interpreted by the receiving processor.

This patch adds the operations defined in the Greybus specification to
greybus_protocols.h, this involves adding the
SVC_TIMESYNC_WAKE_PINS_ACQUIRE and SVC_TIMESYNC_WAKE_PINS_RELEASE commands
and moving the 'strobe_mask' parameter from 'struct
gb_svc_timesync_enable_request' to 'struct
gb_svc_timesync_wd_pins_acquire_request' since the communication of the
strobe_mask will be communicated before preparing any of the bridges to
receive the TimeSync pulses.

A separate patch to the greybus specification describes the transition
between the wake sub-state and the timesync sub-state.

Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Reviewed-by: Vaibhav Hiremath <vaibhav.hiremath@linaro.org>
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>