configs/beaglebone: bump Linux to 6.12.23-ti-arm32-r11 and U-Boot to 2025.07

The patch bumps the Linux kernel to version 6.12.23-ti-arm32-r11 and
U-Boot to version 2025.07.

Tested on beaglebone black.

Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
Signed-off-by: Julien Olivain <ju.o@free.fr>