mvebu: set kernel testing version to 5.4

Signed-off-by: DENG Qingfang <[email protected]>

target/linux/mvebu/Makefile

@@ -12,6 +12,7 @@ FEATURES:=fpu usb pci pcie gpio nand squashfs ramdisk boot-part rootfs-part
 SUBTARGETS:=cortexa9 cortexa53 cortexa72
 
 KERNEL_PATCHVER:=4.19
+KERNEL_TESTING_PATCHVER:=5.4
 
 include $(INCLUDE_DIR)/target.mk