bcm27xx-userland: update to latest version

bcm27xx-userland: update to latest version

This is the last update for bcm27xx-userland as it has been
deprecated but funcional up to raspberry pi 5.

96a7334 README: Update to make it clear that most code in this repo is deprecated
3c97f76 userland: dtoverlay: /boot/firmware is a valid path
153a235 Assorted clang static analysis fixes
eca070c bcm_host: Update kms/fkms check for pi5
06a7618 dtoverlay: Support bcm2712 as a platform
0489c07 dtoverlay: Add dtoverlay_first/next_subnode
a1c7f81 dtoverlay: Support literal assignments of path strings
44a3953 raspivid: Also flush PTS file if flush is enabled
cc1ca18 userland: dtoverlay: Use os_prefix if set
9d5250f libfdt: Add null-ptr check for prop-data to resolve clang --analyzer warning
50527c6 mmal: Only include Videocore components if not running on Videocore
df245ea tvservice: Update unsupported message to recommend kmsprint
de0cfe8 dtoverlay: Fix clang warnings
0182f05 dtoverlay: Fix various compiler warnings
2a6306b dtoverlay: Fix path rebasing and exports
d1e92d7 dtoverlay: Add support for string escape sequences
b1ee39e gencmd: Add a fallback to mailbox interface if vchiq is not available
54fd97a hello_pi: Fix some build issues

Signed-off-by: Marty Jones <mj8263788@gmail.com>
(cherry picked from commit 3df664101a18cf835c97ce5f0fbcc6357a16c101)
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>