asm-generic: add generic versions of common headers

These are all kernel internal interfaces that get copied
around a lot. In most cases, architectures can provide
their own optimized versions, but these generic versions
can work as well.

I have tried to use the most common contents of each
header to allow existing architectures to migrate easily.

Thanks to Remis for suggesting a number of cleanups.

Signed-off-by: Remis Lima Baima <remis.developer@googlemail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
diff --git a/include/asm-generic/linkage.h b/include/asm-generic/linkage.h
new file mode 100644
index 0000000..fef7a01
--- /dev/null
+++ b/include/asm-generic/linkage.h
@@ -0,0 +1,8 @@
+#ifndef __ASM_GENERIC_LINKAGE_H
+#define __ASM_GENERIC_LINKAGE_H
+/*
+ * linux/linkage.h provides reasonable defaults.
+ * an architecture can override them by providing its own version.
+ */
+
+#endif /* __ASM_GENERIC_LINKAGE_H */