KVM: arm64: nv: Honor guest hypervisor's FP/SVE traps in CPTR_EL2

KVM: arm64: nv: Honor guest hypervisor's FP/SVE traps in CPTR_EL2

Start folding the guest hypervisor's FP/SVE traps into the value
programmed in hardware. Note that as of writing this is dead code, since
KVM does a full put() / load() for every nested exception boundary which
saves + flushes the FP/SVE state.

However, this will become useful when we can keep the guest's FP/SVE
state alive across a nested exception boundary and the host no longer
needs to conservatively program traps.

Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240620164653.1130714-12-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>