iwlegacy: ensure loop counter addr does not wrap and cause an infinite loop

commit c2f9a4e4 upstream.

The loop counter addr is a u16 where as the upper limit of the loop
is an int. In the unlikely event that the il->cfg->eeprom_size is
greater than 64K then we end up with an infinite loop since addr will
wrap around an never reach upper loop limit. Fix this by making addr
an int.

Addresses-Coverity: ("Infinite loop")
Fixes: be663ab6 ("iwlwifi: split the drivers for agn and legacy devices 3945/4965")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Stanislaw Gruszka <stf_xl@wp.pl>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
[bwh: Backported to 3.16: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>