staging: Make some structures static

This was done using a semantic patch (http://coccinelle.lip6.fr/) that
checks that the declaration is not inside a function definition, that the
defined variable is not exported using EXPORTED_SYMBOL, etc, and that the
defined variable does not occur in any other file.  If these conditions
hold, static is added before the declaration.

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>