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-5.10/600-bridge_offload.patch

@@ -1,3 +1,31 @@
+From: Felix Fietkau <nbd@nbd.name>
+Subject: bridge: Add a fast path for the bridge code
+
+This caches flows between MAC addresses on separate ports, including their VLAN
+in order to bypass the normal bridge forwarding code.
+In my test on MT7622, this reduces LAN->WLAN bridging CPU usage by 6-10%,
+potentially even more on weaker platforms
+
+Submitted-by: Felix Fietkau <nbd@nbd.name>
+---
+ include/linux/if_bridge.h                     |   1 +
+ net/bridge/Makefile                           |   2 +-
+ net/bridge/br.c                               |   8 +++
+ net/bridge/br_device.c                        |   7 +++
+ net/bridge/br_forward.c                       |   3 ++
+ net/bridge/br_if.c                            |   7 ++-
+ net/bridge/br_input.c                         |   5 ++
+ net/bridge/br_offload.c                       | 436 +++++++++++++++
+ net/bridge/br_private.h                       |  22 ++++-
+ net/bridge/br_private_offload.h               |  21 +++++
+ net/bridge/br_stp.c                           |   3 +
+ net/bridge/br_sysfs_br.c                      |  35 ++++++
+ net/bridge/br_sysfs_if.c                      |   2 +
+ net/bridge/br_vlan_tunnel.c                   |   3 ++
+ 14 files changed, 552 insertions(+), 3 deletions(-)
+ create mode 100644 net/bridge/br_offload.c
+ create mode 100644 net/bridge/br_private_offload.h
+
 --- a/include/linux/if_bridge.h
 +++ b/include/linux/if_bridge.h
 @@ -57,6 +57,7 @@ struct br_ip_list {