FROMGIT: KVM: arm64: Move host EL1 code out of hyp/ directory

kvm/hyp/reserved_mem.c contains host code executing at EL1 and is not
linked into the hypervisor object. Move the file into kvm/pkvm.c and
rework the headers so that the definitions shared between the host and
the hypervisor live in asm/kvm_pkvm.h.

Signed-off-by: Will Deacon <will@kernel.org>
Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211202171048.26924-4-will@kernel.org
(cherry picked from commit 9429f4b0
 git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git

 next)
Bug: 209777660
Signed-off-by: Will Deacon <willdeacon@google.com>
Change-Id: Ic53c6ef5262e473e61bfdd44204b6a6725035827