H6 and H616 SPL code has a few writes to unknown PRCM registers. Now that we know what they are, let's replace magic offsets with proper register names. Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com> Reviewed-by: Samuel Holland <samuel@sholland.org> Signed-off-by: Andre Przywara <andre.przywara@arm.com>