staging: ks7010: add struct comment to ks_sdio_card

ks_sdio_card structure description does not have a kernel doc format
comment.

Add kernel doc format comment to struct ks_sdio_card.

Signed-off-by: Tobin C. Harding <me@tobin.cc>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>