brcmsmac: get board and chip info from bcma

bcma now provide this data and brcmsmac should get it from there and
not parse it by its self.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Tested-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>