Pass a private data pointer to macros and functions. This makes it easy
to later on make run time decisions. This patch does not change any logic.
These changes should be optimized away during compilation.

V2 changes the macro argument name from "priv" to "lp".
Signed-off-by: NMagnus Damm <damm@igel.co.jp>
Acked-by: NNicolas Pitre <nico@cam.org>
Signed-off-by: NJeff Garzik <jeff@garzik.org>