If the SPI queue is running during system suspend, the system may lock
up.

Fix this by stopping/restarting the queue during system suspend/resume
by calling spi_master_suspend()/spi_master_resume() from the PM
callbacks.  In-kernel users will receive an -ESHUTDOWN error while
system suspend/resume is in progress.
Signed-off-by: NGaku Inami <gaku.inami.xw@bp.renesas.com>
Signed-off-by: NHiromitsu Yamasaki <hiromitsu.yamasaki.ym@renesas.com>
[geert: Cleanup, reword]
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NMark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org