staging: rtl8192u: Fix potential infinite loop

staging: rtl8192u: Fix potential infinite loop

The for-loop iterates with a u8 loop counter i and compares this
with the loop upper limit of riv->ieee80211->LinkDetectInfo.SlotNum
that is a u16 type. There is a potential infinite loop if SlotNum
is larger than the u8 loop counter. Fix this by making the loop
counter the same type as SlotNum.

Addresses-Coverity: ("Infinite loop")
Fixes: 8fc8598e61f6 ("Staging: Added Realtek rtl8192u driver to staging")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20210407150308.496623-1-colin.king@canonical.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>