KVM: arm64: Pass walk flags to kvm_pgtable_stage2_mkyoung

KVM: arm64: Pass walk flags to kvm_pgtable_stage2_mkyoung

kvm_pgtable_stage2_mkyoung currently assumes that it is being called
from a 'shared' walker, which will not be true once called from pKVM.
To allow for the re-use of that function, make the walk flags one of
its parameters.

Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20241218194059.3670226-6-qperret@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>