configs/sipeed_licheepi_nano_defconfig: fix missing linux headers
The build failed with:
Incorrect selection of kernel headers: expected 6.8.x, got 6.5.x
Fixes: https://gitlab.com/buildroot.org/buildroot/-/jobs/6498278078
Signed-off-by: Gero Schwäricke <gero.schwaericke@posteo.de>
Signed-off-by: Romain Naour <romain.naour@smile.fr>