ath79: Convert incorrect 5.10 and 5.15 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/ath79/patches-5.15/404-mtd-cybertan-trx-parser.patch

@@ -1,3 +1,21 @@
+From: Christian Lamparter <chunkeey@gmail.com>
+Subject: [PATCH] ath79: port cybertan_part from ar71xx
+
+This patch ports the cybertan_part code from ar71xx and converts the
+driver to a DT-supported mtd parser. As a result, it will no longer
+add the u-boot, nvram and art partitions, which were never part of
+the special Cybertan header.
+
+Instead these partitions have to be specified in the DT, which has the
+upside of making it possible to add properties (i.e.: read-only), labels
+and references to these important partitions.
+
+Submitted-by: Christian Lamparter <chunkeey@gmail.com>
+---
+ drivers/mtd/parsers/Makefile                  | 1 +
+ drivers/mtd/parsers/Kconfig                   | 8 ++++++++
+ 2 files changed, 9 insertions(+)
+
 --- a/drivers/mtd/parsers/Makefile
 +++ b/drivers/mtd/parsers/Makefile
 @@ -8,6 +8,7 @@ obj-$(CONFIG_MTD_OF_PARTS)		+= ofpart.o