[][openwrt][common][app][Fix switch cmd netlink issue on mt7988]

[Description]
Fix switch cmd netlink issue on mt7988.
Fixes: ("[openwrt][common][app][Refactor switch command to support switches
with different design]") which does not consider mt7988 internal switch
support properly.

[Release-log]
N/A

Change-Id: Idbacd48d4422426e2df5cf15c13926b80481efc6
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/8781435
1 file changed