KVM: Rename x86_emulate.c to emulate.c

We're in arch/x86, what could we possibly be emulating?

Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 1aa7e6d..c0e9427 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2759,7 +2759,7 @@
 	kvm_clear_exception_queue(vcpu);
 	vcpu->arch.mmio_fault_cr2 = cr2;
 	/*
-	 * TODO: fix x86_emulate.c to use guest_read/write_register
+	 * TODO: fix emulate.c to use guest_read/write_register
 	 * instead of direct ->regs accesses, can save hundred cycles
 	 * on Intel for instructions that don't read/change RSP, for
 	 * for example.