asm-generic/unaligned.h: dynamic default unaligned accesses

This is based on the asm-arm/unaligned.h, but made generic so all arches
that cannot do unaligned accesses can utilize it.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>

include/asm-generic/unaligned.h

+#ifndef _GENERIC_UNALIGNED_H
+#define _GENERIC_UNALIGNED_H
+
+#include <asm/byteorder.h>
+
+#include <linux/unaligned/le_byteshift.h>
+#include <linux/unaligned/be_byteshift.h>
+#include <linux/unaligned/generic.h>
+
+/*
+ * Select endianness
+ */
+#if defined(__LITTLE_ENDIAN)
+#define get_unaligned	__get_unaligned_le
+#define put_unaligned	__put_unaligned_le
+#elif defined(__BIG_ENDIAN)
+#define get_unaligned	__get_unaligned_be
+#define put_unaligned	__put_unaligned_be
+#else
+#error invalid endian
+#endif
+
+#endif