Revert " arch: arm: omap4: bump 307MHz GPU to 384MHz without increasing the vo…"

This reverts commit 6931d8881d98de8b4e2c7669de1fa10bd327433e.
Add 512Mhz GPU slot and lower voltages of 384Mhz and 512Mhz GPU slots

Signed-off-by: Dan Trifan <jimsth@gmail.com>

Conflicts:
	arch/arm/mach-omap2/opp4xxx_data.c