SGI IA64 UV: fix ia64 build error in the linux-next tree

Fix the ia64 build error that occurs in the linux-next tree by introducing
an ia64 version of uv.h.

Additionally, clean up the usage of is_uv_system().

Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/drivers/misc/sgi-xp/xp.h b/drivers/misc/sgi-xp/xp.h
index 069ad3a..2275126 100644
--- a/drivers/misc/sgi-xp/xp.h
+++ b/drivers/misc/sgi-xp/xp.h
@@ -15,21 +15,19 @@
 
 #include <linux/mutex.h>
 
+#if defined CONFIG_X86_UV || defined CONFIG_IA64_SGI_UV
 #include <asm/uv/uv.h>
+#define is_uv()		is_uv_system()
+#endif
 
-#ifdef CONFIG_IA64
+#ifndef is_uv
+#define is_uv()		0
+#endif
+
+#if defined CONFIG_IA64
 #include <asm/system.h>
 #include <asm/sn/arch.h>	/* defines is_shub1() and is_shub2() */
 #define is_shub()	ia64_platform_is("sn2")
-#ifdef CONFIG_IA64_SGI_UV
-#define is_uv()		ia64_platform_is("uv")
-#else
-#define is_uv()		0
-#endif
-#endif
-#ifdef CONFIG_X86_64
-#include <asm/genapic.h>
-#define is_uv()		is_uv_system()
 #endif
 
 #ifndef is_shub1
@@ -44,10 +42,6 @@
 #define is_shub()	0
 #endif
 
-#ifndef is_uv
-#define is_uv()		0
-#endif
-
 #ifdef USE_DBUG_ON
 #define DBUG_ON(condition)	BUG_ON(condition)
 #else