This patch adds feature negotiation and ssr ack feature between
local host and remote processor. Local host can negotiate on common
features supported with remote processor.

When ssr ack feature bit is set, the remote processor will tell local
host when it is reinitialized. All clients registered for falling edge
interrupts will be notified when the smp2p entries are cleared for ssr.
Signed-off-by: Chris Lew <clew@codeaurora.org>
Signed-off-by: Deepak Kumar Singh <deesin@codeaurora.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/1633450403-21281-1-git-send-email-deesin@codeaurora.org