ar71xx: fix Mikrotik board detection

Fix a typo in the machine type being extracted from /proc/cpuinfo
which causes all Mikrotik board to be undetected properly.

This lead to sysupgrade issues and probably some others too.

Fixes: 76c963bb01 ("ar71xx: base-files: fix board detect on new MikroTik devices")

Signed-off-by: Koen Vandeputte <koen.vandeputte@ncentric.com>

target/linux/ar71xx/base-files/lib/ar71xx.sh

@@ -1001,7 +1001,7 @@ ar71xx_board_detect() {
 	*"MAC1200R")
 		name="mc-mac1200r"
 		;;
-	"MikroTik"*)
+	"Mikrotik"*)
 		name=$(mikrotik_board_detect "$machine")
 		;;
 	*"MiniBox V1.0")