gsmi: Add GSMI commands to log S0ix info

Add new GSMI commands (GSMI_CMD_LOG_S0IX_SUSPEND = 0xa,
GSMI_CMD_LOG_S0IX_RESUME = 0xb) that allow firmware to log any
information during S0ix suspend/resume paths.

Traditional ACPI suspend S3 involves BIOS both during the suspend and
the resume paths. However, modern suspend type like S0ix does not
involve firmware on either of the paths. This command gives the
firmware an opportunity to log any required information about the
suspend and resume operations e.g. wake sources.

Additionally, this change adds a module parameter to allow platforms
to specifically enable S0ix logging if required. This prevents any
other platforms from unnecessarily making a GSMI call which could have
any side-effects.

Tested by verifying that wake sources are correctly logged in eventlog.

Signed-off-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Rajat Jain <rajatja@chromium.org>
Signed-off-by: Furquan Shaikh <furquan@google.com>
Tested-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
[zwisler: update changelog for upstream]
Signed-off-by: Ross Zwisler <zwisler@google.com>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>