kernel v5.4.257-armv7-rt-x66.2 rebase external git projects and rt: v5.4.257-rt87

BBDTBS: https://git.beagleboard.org/beagleboard/BeagleBoard-DeviceTrees/-/commit/f72c40d59d211740c0970b0110d6f2cf53b96d16
RT: patch-5.4.257-rt87.patch.xz
WIRELESS_REGDB: https://git.kernel.org/pub/scm/linux/kernel/git/sforshee/wireless-regdb.git/commit/?id=991b1ef696b7a034a5bf001cf31ab7735888c6e1
TI_AMX3_CM3: http://git.ti.com/gitweb/?p=processor-firmware/ti-amx3-cm3-pm-firmware.git;a=commit;h=fb484c5e54f2e31cf0a338d2927a06a2870bcc2c
WPANUSB: https://git.beagleboard.org/beagleconnect/linux/wpanusb/-/commit/6aa9bf65b9d88a2c9a111e7b4aed03de2be9413d
BCFSERIAL: https://git.beagleboard.org/beagleconnect/linux/bcfserial/-/commit/db467023bd136c97c2e13c3a8b9e41dbdfafbc66



Signed-off-by: Robert Nelson <robertcnelson@gmail.com>