KVM: nSVM: split out __nested_vmcb_check_controls

Remove the struct vmcb_control_area parameter from nested_vmcb_check_controls,
for consistency with the functions that operate on the save area.  This
way, VMRUN uses the version without underscores for both areas, while
KVM_SET_NESTED_STATE uses the version with underscores.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>