MAINTAINERS: brcm80211: Update F: pattern

commit fc2d6e57
("staging: brcm80211: remove brcm80211 driver from the staging tree")
moved the files, update the F: pattern.

CC: John W. Linville <linville@tuxdriver.com>
CC: Arend van Spriel <arend@broadcom.com>
CC: Greg Kroah-Hartman <gregkh@suse.de>

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>