configs/nvidia_bf3: set BR2_cortex_a78
The nvidia BlueField-3 DPU includes Arm Cortex-A78 Hercules
processors. See [1].
The Cortex-A78 support was added in Buildroot in commit [2].
This commit adds BR2_cortex_a78=y in nvidia_bf3_defconfig to enable
optimisations for this processor.
[1] https://www.nvidia.com/en-us/networking/products/data-processing-unit/
[2] https://gitlab.com/buildroot.org/buildroot/-/commit/f4690c2bfd7d51c614d09ff470e725c795bab980
Cc: Vincent Jardin <vjardin@free.fr>
Tested-by: Vincent Jardin <vjardin@free.fr>
Signed-off-by: Julien Olivain <ju.o@free.fr>