x86: 6.6: set testing kernel

Allow selecting 6.6 as testing kernel on x86.

Signed-off-by: Mieczyslaw Nalewaj <[email protected]>

target/linux/x86/Makefile

@@ -11,6 +11,7 @@ FEATURES:=squashfs ext4 vdi vmdk vhdx pcmcia targz fpu boot-part rootfs-part
 SUBTARGETS:=generic legacy geode 64
 
 KERNEL_PATCHVER:=6.1
+KERNEL_TESTING_PATCHVER:=6.6
 
 KERNELNAME:=bzImage