ANDROID: KVM: arm64: Update vcpu state with live value of VBAR_EL1 on injecting an exception

If the injection happens very early, when VBAR_EL1 has just been
set, it's value wouldn't be up to date in the vcpu structure,
resulting in it being clobbered before returning to the guest
with the injected exception, which the guest wouldn't be able to
handle properly. Although this probably means that the guest
cannot properly run, it makes debugging this difficult.

Bug: 357781595
Change-Id: Iacc9cdf46a3da7879d08fb03666ce42d7b0bbdbf
Signed-off-by: Fuad Tabba <tabba@google.com>