mwifiex: do not hint regulatory domain with f/w country code

We will use world regulatory domain (country 00) as default
when driver is loaded. Later after a successful association
cfg80211 will change the regulatory domain to a specific country
if the AP has advertised country IE.

Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>