generic: Convert incorrect generic/5.10 patches

OpenWRT's developer guide prefers having actual patches so they an be
sent upstream more easily.

However, in this case, Adding proper fields also allows for `git am` to
properly function. Some of these patches are quite old, and lack much
traceable history.

This commit tries to rectify that, by digging in the history to find
where and how it was first added.

It is by no means perfect and also shows some patches that should have
been long gone.

Signed-off-by: Olliver Schinagl <oliver@schinagl.nl>

target/linux/generic/hack-5.10/430-mtk-bmt-support.patch

@@ -1,3 +1,14 @@
+From 11425c9de29c8b9c5e4d7eec163a6afbb7fbdce2 Mon Sep 17 00:00:00 2001
+From: Felix Fietkau <nbd@nbd.name>
+Date: Thu, 9 Apr 2020 09:53:24 +0200
+Subject: mediatek: Implement bad-block management table support
+
+Submitted-by: Felix Fietkau <nbd@nbd.name>
+---
+ drivers/mtd/nand/Kconfig                      |   4 ++++
+ drivers/mtd/nand/Makefile                     |   1 +
+ 2 files changed, 5 insertions(+)
+
 --- a/drivers/mtd/nand/Kconfig
 +++ b/drivers/mtd/nand/Kconfig
 @@ -15,6 +15,10 @@ config MTD_NAND_ECC