x86: move i386 and x86_64 Makefiles to arch/x86

Moving the ARCH specific Makefiles for i386 and x86_64
required a litle bit tweaking in the top-lvel Makefile.

SRCARCH is now set in the top-level Makefile
because we need this info to include the correct
arch Makefile.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
new file mode 100644
index 0000000..65077d7
--- /dev/null
+++ b/arch/x86/Makefile
@@ -0,0 +1,13 @@
+# Unified Makefile for i386 and x86_64
+
+# No need to remake these files
+$(srctree)/arch/x86/Makefile%: ;
+
+ifeq ($(ARCH),i386)
+        include $(srctree)/arch/x86/Makefile_32
+else
+        include $(srctree)/arch/x86/Makefile_64
+endif
+
+
+