staging: brcm80211: remove struct brcmf_sdio_card from brcmfmac

Use brcmf_sdio_dev as the unified structure to store information
of wifi dongle

Reviewed-by: Roland Vossen <rvossen@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>