kvm: vmx: fix coccinelle warnings

This fixes the following coccinelle warning:

WARNING: return of 0/1 in function 'vmx_need_emulation_on_page_fault'
with return type bool

Return false instead of 0.

Signed-off-by: Yi Wang <wang.yi59@zte.com.cn>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>