[][Enable PCIe Gen3 driver for mt7986]

[Description]
Change PCIe node, and enable PCIe Gen3 driver for mt7986.

[Release-log]
N/A

Change-Id: I0c0f39f23ad8fcfef86bb0735418f11587af9e41
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/4706613
4 files changed