brcmsmac: remove dependency on CRC8 and CRC_CCITT

There is no code in brcmsmac that uses a function from CRC8 or
CRC_CCITT any more. Building brcmsmac with these two disabled works
without any problems. This was probably only used by the bus code which
was replaced by bcma some time ago.

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