ARM: KVM: __kvm_vcpu_run function return result fix in BE case

The __kvm_vcpu_run function returns a 64-bit result in two registers,
which has to be adjusted for BE case.

Signed-off-by: Victor Kamensky <victor.kamensky@linaro.org>
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>