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-5.10/205-kconfig-exit.patch

@@ -1,3 +1,20 @@
+From: David Bauer <mail@david-bauer.net>
+Subject: Kconfig: exit on unset symbol
+
+When a target configuration has unset Kconfig symbols, the build will
+fail when OpenWrt is compiled with V=s and stdin is connected to a tty.
+
+In case OpenWrt is compiled without either of these preconditions, the
+build will succeed with the symbols in question being unset.
+
+Modify the kernel configuration in a way it fails on unset symbols
+regardless of the aforementioned preconditions.
+
+Submitted-by: David Bauer <mail@david-bauer.net>
+---
+ scripts/kconfig/conf.c                                |  2 +
+ 1 files changed, 2 insertions(+)
+
 --- a/scripts/kconfig/conf.c
 +++ b/scripts/kconfig/conf.c
 @@ -215,6 +215,8 @@ static int conf_sym(struct menu *menu)