mwifiex: move under marvell vendor directory

Part of reorganising wireless drivers directory and Kconfig.

Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/Kconfig

@@ -152,7 +152,6 @@ source "drivers/net/wireless/realtek/rtlwifi/Kconfig"
 source "drivers/net/wireless/realtek/rtl8xxxu/Kconfig"
 source "drivers/net/wireless/ti/Kconfig"
 source "drivers/net/wireless/zd1211rw/Kconfig"
-source "drivers/net/wireless/mwifiex/Kconfig"
 source "drivers/net/wireless/rsi/Kconfig"
 
 endif # WLAN