rockchip: enable testing kernel version with 6.1 version

Enable testing kernel version with 6.1 kernel version.

Signed-off-by: Tianling Shen <[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:=5.15
+KERNEL_TESTING_PATCHVER:=6.1
 
 define Target/Description
 	Build firmware image for Rockchip SoC devices.