aarch64: move the bulk of EL3 initialization to C

The majority of state that we initialize at EL3 is necessary for code at
lower ELs to function, but isnt' necessary for the boot-wrapper itself.
Given that, it would be better to write this in C where it can be
written mode clearly, and where it will be possible to add logging/debug
logic.

This patch migrates the AArch64 EL3 initialization to C.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
4 files changed