wifi: cfg80211: Fix return value in scan logic

The reporter noticed a warning when running iwlwifi:

WARNING: CPU: 8 PID: 659 at mm/page_alloc.c:4453 __alloc_pages+0x329/0x340

As cfg80211_parse_colocated_ap() is not expected to return a negative
value return 0 and not a negative value if cfg80211_calc_short_ssid()
fails.

Fixes: c8cb5b85 ("nl80211/cfg80211: support 6 GHz scanning")
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217675


Signed-off-by: Ilan Peer <ilan.peer@intel.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230723201043.3007430-1-ilan.peer@intel.com