brcmsmac: remove _ai_clkctl_cc()

This is now done by calling bcma_core_set_clockmode()

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>