nl80211/cfg80211: fix potential infinite loop

nl80211/cfg80211: fix potential infinite loop

The for-loop iterates with a u8 loop counter and compares this
with the loop upper limit of request->n_ssids which is an int type.
There is a potential infinite loop if n_ssids is larger than the
u8 loop counter, so fix this by making the loop counter an int.

Addresses-Coverity: ("Infinite loop")
Fixes: c8cb5b854b40 ("nl80211/cfg80211: support 6 GHz scanning")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20201029222407.390218-1-colin.king@canonical.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>