support/testing: update zfs tests to Linux 6.12.9

The previous version, Linux 5.15.35, is outdated.
Upgrade to the latest LTS release.

Signed-off-by: José Luis Salvador Rufo <salvador.joseluis@gmail.com>
Signed-off-by: Julien Olivain <ju.o@free.fr>

support/testing/tests/package/test_zfs.py

@@ -13,7 +13,7 @@ class TestZfsBase(infra.basetest.BRTest):
         BR2_ROOTFS_DEVICE_CREATION_DYNAMIC_EUDEV=y
         BR2_LINUX_KERNEL=y
         BR2_LINUX_KERNEL_CUSTOM_VERSION=y
-        BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="5.15.35"
+        BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="6.12.9"
         BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG=y
         BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="board/qemu/x86_64/linux.config"
         BR2_LINUX_KERNEL_NEEDS_HOST_LIBELF=y