Staging: w35und: remove unnecessary os_common.h header file

Convert code to include sysdef.h directly and remove unnecessary os_common.h
header file.

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