dts: nxp: wifi: fix Wi-Fi spelling

Spell Wi-Fi properly in binding description

Signed-off-by: Benjamin Cabé <benjamin@zephyrproject.org>

Author: kartben

dts/bindings/wifi/nxp,wifi.yaml

@@ -3,7 +3,7 @@
 # SPDX-License-Identifier: Apache-2.0
 
 description: |
-    NXP Wifi Module
+    NXP Wi-Fi Module
 
 compatible: "nxp,wifi"