[][mtd: spinand: rebase GD device support]

[Description]
Fix and rebase GD device support.
Delete previous added Micron & GD devices which already exists in backport part.

[Release-log]
N/A

Change-Id: I349ab37e134eb87efee040fa989d038982d59d46
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/5746854
3 files changed