rockchip: add kernel 6.6 as testing kernel

Add kernel 6.6 as testing kernel

Signed-off-by: Antonio Flores <[email protected]>

target/linux/rockchip/Makefile

@@ -8,6 +8,7 @@ FEATURES:=ext4 audio usb usbgadget display gpio fpu pci pcie rootfs-part boot-pa
 SUBTARGETS:=armv8
 
 KERNEL_PATCHVER:=6.1
+KERNEL_TESTING_PATCHVER:=6.6
 
 define Target/Description
 	Build firmware image for Rockchip SoC devices.