wlan: Correct db.txt for a set of countries.

Correct the channel list and tx power values for countries
with alpha2 IL, MX, ZA and TW.

Change-Id: I735a153ef1e87c1022f175ac360d675071d1ec2a
CRs-Fixed: 640859
Signed-off-by: Amar Singhal <asinghal@codeaurora.org>