remove dummy asm/kvm.h files

This patch removes the dummy asm/kvm.h files on architectures not (yet)
supporting KVM and uses the same conditional headers installation as
already used for a.out.h .

Also removed are superfluous install rules in the s390 and x86 Kbuild
files (they are already in Kbuild.asm).

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/include/linux/Kbuild b/include/linux/Kbuild
index 71d70d1..402c8f5 100644
--- a/include/linux/Kbuild
+++ b/include/linux/Kbuild
@@ -256,7 +256,9 @@
 unifdef-y += kernelcapi.h
 unifdef-y += kernel.h
 unifdef-y += keyboard.h
+ifneq ($(wildcard $(srctree)/include/asm-$(SRCARCH)/kvm.h),)
 unifdef-y += kvm.h
+endif
 unifdef-y += llc.h
 unifdef-y += loop.h
 unifdef-y += lp.h