x86: Export asm/{svm.h,vmx.h,perf_regs.h}

Export asm/{svm.h,vmx.h,perf_regs.h} so that they can be disintegrated.

It looks from previous commits that the first two should have been exported,
but the header-y lines weren't added to the Kbuild.

I'm guessing that asm/perf_regs.h should be exported too.
Signed-off-by: David Howells <dhowells@redhat.com>

arch/x86/include/asm/Kbuild

@@ -12,6 +12,7 @@ header-y += mce.h
 header-y += msr-index.h
 header-y += msr.h
 header-y += mtrr.h
+header-y += perf_regs.h
 header-y += posix_types_32.h
 header-y += posix_types_64.h
 header-y += posix_types_x32.h
@@ -19,8 +20,10 @@ header-y += prctl.h
 header-y += processor-flags.h
 header-y += ptrace-abi.h
 header-y += sigcontext32.h
+header-y += svm.h
 header-y += ucontext.h
 header-y += vm86.h
+header-y += vmx.h
 header-y += vsyscall.h
 
 genhdr-y += unistd_32.h