yocto-bsp: set temporary preferred version for genericarm64

We want to introduce the 6.10 linux-yocto recipe, but genericarm64
hasn't been valided for it yet. As such, let's temporarily set the
preferred version to 6.6 so the builds don't break.

(From meta-yocto rev: 6ba3b6f15bf2460432da3a3aee782976e778381c)

Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta-yocto-bsp/conf/machine/genericarm64.conf

@@ -12,6 +12,7 @@ MACHINE_FEATURES = "acpi alsa bluetooth efi keyboard pci qemu-usermode rtc scree
 
 KERNEL_IMAGETYPE = "Image"
 PREFERRED_PROVIDER_virtual/kernel ?= "linux-yocto"
+PREFERRED_VERSION_linux-yocto ?= "6.6%"
 
 # Install all the kernel modules into the rootfs
 MACHINE_EXTRA_RRECOMMENDS += "kernel-modules"