arm: KVM: keep arm vfp/simd exit handling consistent with arm64

After enhancing arm64 FP/SIMD exit handling, ARMv7 VFP exit branch is moved
to guest trap handling. This allows us to keep exit handling flow between both
architectures consistent.

Signed-off-by: Mario Smarduch <m.smarduch@samsung.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>