rtlwifi: fix usage of freq_reg_info()

freq_reg_info() expects KHz and not MHz, fix this. In
this case we'll now be getting the no-ir flags cleared
on channels for any channel when the country IE trusts
that channel.

@@
struct ieee80211_channel *ch;
struct wiphy *wiphy;
const struct ieee80211_reg_rule *rule;
@@

-rule = freq_reg_info(wiphy, ch->center_freq);
+rule = freq_reg_info(wiphy, MHZ_TO_KHZ(ch->center_freq));

Generated-by: Coccinelle SmPL
Cc: Julia Lawall <julia.lawall@lip6.fr>
Cc: Peter Senna Tschudin <peter.senna@gmail.com>
Cc: Larry Finger <Larry.Finger@lwfinger.net>
Reported-by: Mihir Shete <smihir@qti.qualcomm.com>
Signed-off-by: Luis R. Rodriguez <mcgrof@do-not-panic.com>
Acked-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>