staging: brcm80211: remove unnecessary include from nvram_ro.c

Source file included bcmotp.h but did not use any declared item
from that include file so it can safely be removed.

Reviewed-by: Roland Vossen <rvossen@broadcom.com>
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>