x86/compat: Don't build the 32-bit VDSO if not needed

Build the 32-bit vdso only for native 32-bit or 32-bit compat is
enabled.  x32 should not force it to build.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1434974121-32575-7-git-send-email-brgerst@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index 1c9f750..4345431 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -177,7 +177,7 @@
 	return ret;
 }
 
-#if defined(CONFIG_X86_32) || defined(CONFIG_COMPAT)
+#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
 static int load_vdso32(void)
 {
 	int ret;
@@ -219,8 +219,11 @@
 		return map_vdso(&vdso_image_x32, true);
 	}
 #endif
-
+#ifdef CONFIG_IA32_EMULATION
 	return load_vdso32();
+#else
+	return 0;
+#endif
 }
 #endif
 #else