sh_eth: Convert to DEFINE_SIMPLE_DEV_PM_OPS()

sh_eth: Convert to DEFINE_SIMPLE_DEV_PM_OPS()

Convert the Renesas SuperH Ethernet driver from an open-coded dev_pm_ops
structure to DEFINE_SIMPLE_DEV_PM_OPS() and pm_sleep_ptr().  This lets
us drop the checks for CONFIG_PM and CONFIG_PM_SLEEP without impacting
code size, while increasing build coverage.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Tested-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Link: https://patch.msgid.link/ee4def57eb68dd2c32969c678ea916d2233636ed.1756998732.git.geert+renesas@glider.be
Signed-off-by: Jakub Kicinski <kuba@kernel.org>