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>

configs/sipeed_licheepi_nano_defconfig

@@ -9,6 +9,9 @@ BR2_TARGET_GENERIC_GETTY_BAUDRATE_115200=y
 BR2_ROOTFS_POST_IMAGE_SCRIPT="support/scripts/genimage.sh"
 BR2_ROOTFS_POST_SCRIPT_ARGS="-c board/sipeed/licheepi_nano/genimage.cfg"
 
+# Linux headers same as kernel
+BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_6_5=y
+
 # Kernel
 BR2_LINUX_KERNEL=y
 BR2_LINUX_KERNEL_CUSTOM_VERSION=y