ath10k-firmware: do not select the qca988x by default

Do not select the qca988x by default as soon as kmod-ath10k is
selected. We do support more ath10k chips than the qca988x in the
meantime, so this dependency doesn't make sense any longer.

Signed-off-by: Mathias Kresin <dev@kresin.me>

package/firmware/ath10k-firmware/Makefile

@@ -63,7 +63,6 @@ $(eval $(call Download,ath10k-qca9887-board))
 
 define Package/ath10k-firmware-qca988x
 $(Package/ath10k-firmware-default)
-  DEFAULT:=PACKAGE_kmod-ath10k
   TITLE:=ath10k firmware for QCA988x devices
   SECTION:=firmware
   CATEGORY:=Firmware