staging: ks7010: Replace SSID_MAX_SIZE with IEEE80211_MAX_SSID_LEN.

SSID_MAX_SIZE is a constant defined locally in ks_hostif.h, but it should
be replaced with IEEE80211_MAX_SSID_LEN from the kernel's 802.11 header,
of which it is just a copy.

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