staging: brcm80211: absorb linux_osl.h into osl.h

Move code from linux_osl.h into osl.h and delete linux_osl.h, which
created a bunch of checkpatch errors...
I fixed most but volatile warnings will have to be dealt with later.

Signed-off-by: Brett Rudley <brudley@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>