drm/bridge: imx8mp-hdmi-tx: Switch to SYSTEM_SLEEP_PM_OPS()

drm/bridge: imx8mp-hdmi-tx: Switch to SYSTEM_SLEEP_PM_OPS()

Replace SET_SYSTEM_SLEEP_PM_OPS with its modern SYSTEM_SLEEP_PM_OPS()
alternative.

The combined usage of pm_ptr() and SYSTEM_SLEEP_PM_OPS()
allows the compiler to evaluate if the runtime suspend/resume() functions
are used at build time or are simply dead code.

This allows removing the __maybe_unused notation from the runtime
suspend/resume() functions.

Signed-off-by: Fabio Estevam <festevam@denx.de>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20240626230704.708234-1-festevam@gmail.com
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240626230704.708234-1-festevam@gmail.com