firmware: arm_scmi: Convert to SYSTEM_SLEEP_PM_OPS

commit 62d6b81e upstream.

The old SET_SYSTEM_SLEEP_PM_OPS() macro leads to a warning about an
unused function:

  |  drivers/firmware/arm_scmi/scmi_power_control.c:363:12: error:
  | 	'scmi_system_power_resume' defined but not used [-Werror=unused-function]
  |         static int scmi_system_power_resume(struct device *dev)

The proper way to do this these days is to use SYSTEM_SLEEP_PM_OPS()
and pm_sleep_ptr().

Fixes: 9a0658d3 ("firmware: arm_scmi: power_control: Ensure SCMI_SYSPOWER_IDLE is set early during resume")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Peng Fan <peng.fan@nxp.com>
Message-Id: <20250709070107.1388512-1-arnd@kernel.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>