KVM: arm64: pkvm: Move error handling to the end of kvm_hyp_cpu_entry

KVM: arm64: pkvm: Move error handling to the end of kvm_hyp_cpu_entry

We currently handle CPUs having booted at EL1 in the middle of
the kvm_hyp_cpu_entry function. Not only this adversely affects
readability, but this is also at a bizarre spot should more
error handling be added (which we're about to do).

Move the WFE/WFI loop to the end of the function and fix a comment.

Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Link: https://patch.msgid.link/20260321212419.2803972-2-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>