[Buildroot] [RESEND PATCH v3 1/1] configs: add raspberrypi 5 defconfig

[Athaariq Ardhiansyah]

Hello Yann, Gaël, and all

Thanks for finally add Raspberry Pi 5 support. I would like to remind 
you that there is a
lot of bug fixes since current rpi-firmware commit in buildroot. Here is 
the full history of
the fixes:

https://github.com/raspberrypi/firmware/commits/master/boot/bcm2712-rpi-5-b.dtb

Therefore, I recommend you to bump rpi-firmware version and use Linux 
v6.6. I sent a
patch for this before Gaël's patch got merged. Please let me know if I 
need to rebase
and revise the changes. Cheers!

Best regards,
Athaariq Ardhiansyah