mach-tegra: Low Power core overdrive

This overdrive unlocks the low power core (LP)'s full potential of 620 MHz

Signed-off-by: Paul Reioux <reioux@gmail.com>

Conflicts:
	arch/arm/mach-tegra/Kconfig
	arch/arm/mach-tegra/cpuquiet.c
	arch/arm/mach-tegra/tegra3_clocks.c
	arch/arm/mach-tegra/tegra3_speedo.c