mvebu: add 5.10 as a testing kernel

Keep 5.4 as stable until further validation.

Tested on Turris Omnia (Rui Salvaterra) and ESPRESSObin v5 (Tomasz
Maciej Nowak). Cortex-A{53,72} subtargets are only build-tested.

Reviewed-by: Tomasz Maciej Nowak <[email protected]>
Tested-by: Tomasz Maciej Nowak <[email protected]>
Signed-off-by: Rui Salvaterra <[email protected]>
[added comment about tests]
Signed-off-by: Adrian Schmutzler <[email protected]>

target/linux/mvebu/Makefile

@@ -10,7 +10,7 @@ FEATURES:=fpu usb pci pcie gpio nand squashfs ramdisk boot-part rootfs-part
 SUBTARGETS:=cortexa9 cortexa53 cortexa72
 
 KERNEL_PATCHVER:=5.4
-KERNEL_TESTING_PATCHVER:=5.4
+KERNEL_TESTING_PATCHVER:=5.10
 
 include $(INCLUDE_DIR)/target.mk