ipq806x: fix Netgear X4 R7500 ath10k firmware selection

Netgear X4 R7500 comes with a QCA988X. Select a firmware that matches
the ath10k chipset

Signed-off-by: Thomas Reifferscheid <[email protected]>

target/linux/ipq806x/image/Makefile

@@ -194,7 +194,7 @@ define Device/R7500
 	PAGESIZE := 2048
 	BOARD_NAME := r7500
 	DEVICE_TITLE := Netgear Nighthawk X4 R7500
-	DEVICE_PACKAGES := ath10k-firmware-qca99x0
+	DEVICE_PACKAGES := ath10k-firmware-qca988x
 endef
 
 define Device/R7500v2