staging: brcm80211: remove support functions for older chipsets from bcmsrom

The source file contained functions for both older and current chipsets
but the brcmsmac driver does not support the older chipsets so those
functions are removed.
Reviewed-by: Henry Ptasinski <henryp@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>