spi: omap2-mcspi: Restore context always in runtime_resume

We can have the SoC enter off mode also during idle, not just
during suspend. Currently we are handling the CS restore properly
for unused CS only for resume and not for runtime resume.

Let's just move all the context related restore to runtime_resume().

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Mark Brown <broonie@kernel.org>