ar71xx: fix more image build code whitespace/tab issues

Signed-off-by: Felix Fietkau <nbd@nbd.name>

target/linux/ar71xx/image/nand.mk

@@ -21,19 +21,19 @@ endef
 TARGET_DEVICES += mr18
 
 define LegacyDevice/R6100
-	DEVICE_TITLE := NETGEAR R6100
-	DEVICE_PACKAGES := kmod-usb-core kmod-usb-ohci kmod-usb2 kmod-ledtrig-usbdev
+  DEVICE_TITLE := NETGEAR R6100
+  DEVICE_PACKAGES := kmod-usb-core kmod-usb-ohci kmod-usb2 kmod-ledtrig-usbdev
 endef
 LEGACY_DEVICES += R6100
 
 define LegacyDevice/WNDR4300
-	DEVICE_TITLE := NETGEAR WNDR3700v4/WNDR4300
-	DEVICE_PACKAGES := kmod-usb-core kmod-usb-ohci kmod-usb2 kmod-ledtrig-usbdev
+  DEVICE_TITLE := NETGEAR WNDR3700v4/WNDR4300
+  DEVICE_PACKAGES := kmod-usb-core kmod-usb-ohci kmod-usb2 kmod-ledtrig-usbdev
 endef
 LEGACY_DEVICES += WNDR4300
 
 define LegacyDevice/NBG6716
-	DEVICE_TITLE := Zyxel NBG 6716
-	DEVICE_PACKAGES := kmod-rtc-pcf8563 kmod-ath10k
+  DEVICE_TITLE := Zyxel NBG 6716
+  DEVICE_PACKAGES := kmod-rtc-pcf8563 kmod-ath10k
 endef
 LEGACY_DEVICES += NBG6716