KVM: arm64: Rename 'host_kvm' to 'kvm' in pKVM host code

KVM: arm64: Rename 'host_kvm' to 'kvm' in pKVM host code

In hypervisor (EL2) code, it is important to distinguish between the
host's 'struct kvm' and a protected VM's 'struct kvm'. Using 'host_kvm'
as variable name in that context makes this distinction clear.

However, in the host kernel code (EL1), there is no such ambiguity. The
code is only ever concerned with the host's own 'struct kvm' instance.
The 'host_' prefix is therefore redundant and adds unnecessary
verbosity.

Simplify the code by renaming the 'host_kvm' parameter to 'kvm' in all
functions within host-side kernel code (EL1). This improves readability
and makes the naming consistent with other host-side kernel code.

No functional change intended.

Signed-off-by: Fuad Tabba <tabba@google.com>
Tested-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>