When processing a system suspend request we suspend modem endpoints
if they are enabled, and call ipa_cmd_tag_process() (which issues
IPA commands) to ensure the IPA pipeline is cleared.  It is an error
to attempt to issue an IPA command before setup is complete, so this
is clearly a bug.  But we also shouldn't suspend or resume any
endpoints that have not been set up.

Have ipa_endpoint_suspend() and ipa_endpoint_resume() immediately
return if setup hasn't completed, to avoid any attempt to configure
endpoints or issue IPA commands in that case.

Fixes: 84f9bd12 ("soc: qcom: ipa: IPA endpoints")
Tested-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>