ARM: OMAP: Move omap-pm-noop.c local to mach-omap2

This code should be private to mach-omap2.

The only use for it in for omap1 has been in dmtimer.c
to check for context loss. However, omap1 does not
lose context during idle, so the code is not needed.
Further, omap1 timer has OMAP_TIMER_ALWON set, so omap1
was not hitting omap_pm_get_dev_context_loss_count()
test.

Cc: Jon Hunter <jon-hunter@ti.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>