staging: brcm80211: cleanup driver variable references

Throughout the data structures within the driver several references
to the driver variables were stored. As the storage and access
functions are now consolidated into srom.c those references are
no longer needed and have been removed.

Reviewed-by: Roland Vossen <rvossen@broadcom.com>
Reviewed-by: Alwin Beukers <alwin@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>