Staging: w35und: make functions local to wb35tx.c static

While there are no functional changes, the diff is quite large because we need
to shuffle code around to avoid forward declarations.

Acked-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>