[][kernel][mt7988][dts][Remove PEXTP SEL in PCIe node]

[Description]
Remove PCIe PEXTP SEL that already be enabled.

[Release-log]
N/A

Change-Id: Ie51d0decd52db15d140d7e8b9b9d952c5e5dfb02
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/6709532
1 file changed