BACKPORT: FROMGIT: KVM: arm64: Plumb the pKVM MMU in KVM

Introduce the KVM_PGT_CALL() helper macro to allow switching from the
traditional pgtable code to the pKVM version easily in mmu.c. The cost
of this 'indirection' is expected to be very minimal due to
is_protected_kvm_enabled() being backed by a static key.

With this, everything is in place to allow the delegation of
non-protected guest stage-2 page-tables to pKVM, so let's stop using the
host's kvm_s2_mmu from EL2 and enjoy the ride.

BACKPORT: Small conflicts all over the place. Removed now unused code
from mmu.c.

Bug: 357781595
Bug: 235345873
Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Change-Id: I58367c5b21366b9bc973efe2f36dc82d3b6dfc23
Signed-off-by: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20241218194059.3670226-19-qperret@google.com


Signed-off-by: Marc Zyngier <maz@kernel.org>
(cherry picked from commit fce886a6
 git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm next)
Signed-off-by: Quentin Perret <qperret@google.com>