staging: brcm80211: remove brcmu_bprintf and related functions

The functions brcmu_bprintf and brcmu_binit could be replaced by
snprintf kernel function. These are no longer used in both brcm80211
drivers so they have been removed.

Reported-by: Johannes Berg <johannes@sipsolutions.net>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@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>