HID: i2c-hid: Switch to SYSTEM_SLEEP_PM_OPS()

The SYSTEM_SLEEP_PM_OPS() allows us to get rid of '#ifdef
CONFIG_PM_SLEEP', as talked about in commit 1a3c7bb0

 ("PM: core:
Add new *_PM_OPS macros, deprecate old ones").

This change is expected to have no functional effect.

Reviewed-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Benjamin Tissoires <bentiss@kernel.org>
Acked-by: Benjamin Tissoires <bentiss@kernel.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230727101636.v4.5.Ib2a2865bd3c0b068432259dfc7d76cebcbb512be@changeid