[][mtd: mtk-snand: add tuning parameters for mt7622/mt7629/mt7986]

[Description]
Add tuning parameters to fit in each platform. In theory, these values perfectly match our reference board. But in some circumstances, like flash socket installed, you need to tune these values again. This patch allows you to do that.

[Release-log]
N/A

Change-Id: If4d997309abbad3193836b0f4d7a16cced901a20
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/4721474
diff --git a/target/linux/mediatek/files-5.4/drivers/mtd/mtk-snand/mtk-snand-def.h b/target/linux/mediatek/files-5.4/drivers/mtd/mtk-snand/mtk-snand-def.h
index 1a93d93..8058f7b 100644
--- a/target/linux/mediatek/files-5.4/drivers/mtd/mtk-snand/mtk-snand-def.h
+++ b/target/linux/mediatek/files-5.4/drivers/mtd/mtk-snand/mtk-snand-def.h
@@ -115,6 +115,9 @@
 
 	const uint8_t *spare_sizes;
 	uint32_t num_spare_size;
+
+	uint16_t latch_lat;
+	uint16_t sample_delay;
 };
 
 enum mtk_ecc_regs {