arm64: head: Move all finalise_el2 calls to after __enable_mmu

arm64: head: Move all finalise_el2 calls to after __enable_mmu

In the primary boot path, finalise_el2() is called much later than on
the secondary boot or resume-from-suspend paths, and this does not
appear to be intentional.

Since we aim to do as little as possible before enabling the MMU and
caches, align secondary and resume with primary boot, and defer the call
to after the MMU is turned on. This also removes the need to clean
finalise_el2() to the PoC once we enable support for booting with the
MMU on.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20230111102236.1430401-2-ardb@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>