ARM: omap2+: cpufreq: Allow lower maximum frequency when screen is off

Allow userspace to set a lower maximum cpu frequency when the screen
is off.  Ideally userspace should be handling this, but use early
suspend for now.

Change-Id: Ifacd7312757318f10e5600ed9ffec8039cb4bf9b
Signed-off-by: Colin Cross <ccross@android.com>

Conflicts:
	arch/arm/mach-omap2/omap2plus-cpufreq.c