sh_eth: Fix power down vs. is_opened flag ordering

sh_eth_close() does a synchronous power down of the device before
marking it closed.  Revert the order, to make sure the device is never
marked opened while suspended.

While at it, use pm_runtime_put() instead of pm_runtime_put_sync(), as
there is no reason to do a synchronous power down.

Fixes: 7fa2955f

 ("sh_eth: Fix sleeping function called from invalid context")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Sergei Shtylyov <sergei.shtylyov@gmail.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Link: https://lore.kernel.org/r/20210118150812.796791-1-geert+renesas@glider.be
Signed-off-by: Jakub Kicinski <kuba@kernel.org>