kvm: Disable objtool frame pointer checking for vmenter.S

Frame pointers are completely broken by vmenter.S because it clobbers
RBP:

  arch/x86/kvm/svm/vmenter.o: warning: objtool: __svm_vcpu_run()+0xe4: BP used as a scratch register

That's unavoidable, so just skip checking that file when frame pointers
are configured in.

On the other hand, ORC can handle that code just fine, so leave objtool
enabled in the !FRAME_POINTER case.
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Message-Id: <01fae42917bacad18be8d2cbc771353da6603473.1587398610.git.jpoimboe@redhat.com>
Tested-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Fixes: 199cd1d7 ("KVM: SVM: Split svm_vcpu_run inline assembly to separate file")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/Makefile

@@ -3,6 +3,10 @@
 ccflags-y += -Iarch/x86/kvm
 ccflags-$(CONFIG_KVM_WERROR) += -Werror
 
+ifeq ($(CONFIG_FRAME_POINTER),y)
+OBJECT_FILES_NON_STANDARD_vmenter.o := y
+endif
+
 KVM := ../../../virt/kvm
 
 kvm-y			+= $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o \