lguest: remove remaining vmcall

We switch back from using vmcall in 091ebf07a2408f9a56634caa0f86d9360e9af23b
because it was unreliable under kvm, but I missed one (rarely-used) place.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/arch/x86/lguest/i386_head.S b/arch/x86/lguest/i386_head.S
index 863b03a..c8c95e5 100644
--- a/arch/x86/lguest/i386_head.S
+++ b/arch/x86/lguest/i386_head.S
@@ -101,12 +101,8 @@
 	 */
 	pushl %eax
 	movl $LHCALL_SEND_INTERRUPTS, %eax
-	/*
-	 * This is a vmcall instruction (same thing that KVM uses).  Older
-	 * assembler versions might not know the "vmcall" instruction, so we
-	 * create one manually here.
-	 */
-	.byte 0x0f,0x01,0xc1 /* KVM_HYPERCALL */
+	/* This is the actual hypercall trap. */
+	int  $LGUEST_TRAP_ENTRY
 	/* Put eax back the way we found it. */
 	popl %eax
 	ret