staging: brcm80211: remove unused attributes from struct osl_info

Getting rid of the whole osl concept soon this removes most fields
in struct osl_info. Turned out hnddma.c was still using it so this
was fixed and now it gets pointer to bus device from si_info which
it only needs in the attach function for this purpose so reference
to it does not need to be kept. Two unused functions referencing
the removed fields in linux_osl.c also were removed.

Reviewed-by: Brett Rudley <brudley@broadcom.com>
Reviewed-by: Henry Ptasinski <henryp@broadcom.com>
Reviewed-by: Roland Vossen <rvossen@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>