mwifiex: correction in region code to country mapping

EU is not a valid country in db.txt file. Hence regulatory_hint
returns failure if EEPROM provides region code as 0x30. Let's
use FR for 0x30.

Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Cathy Luo <cluo@marvell.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>