Remove an unused struct x86_emulate_ctxt * param from low level helpers
used to access guest FPU state.  The unused param was left behind by
commit 6ab0b9fe ("x86,kvm: remove KVM emulator get_fpu / put_fpu").

No functional change intended.
Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>