x86: move desc_empty to where they belong

This patch moves the (duplicated) desc_empty implementation to desc.h,
where the descriptor things belong.

Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/include/asm-x86/desc.h b/include/asm-x86/desc.h
index e9356a8..e17581a 100644
--- a/include/asm-x86/desc.h
+++ b/include/asm-x86/desc.h
@@ -71,6 +71,12 @@
 
 #endif
 
+static inline int desc_empty(const void *ptr)
+{
+	const u32 *desc = ptr;
+	return !(desc[0] | desc[1]);
+}
+
 #ifdef CONFIG_PARAVIRT
 #include <asm/paravirt.h>
 #else