sunxi: use kernel 6.12 by default

Switch to Linux kernel version 6.12.

Signed-off-by: Zoltan HERPAI <[email protected]>

target/linux/sunxi/Makefile

@@ -10,8 +10,7 @@ BOARDNAME:=Allwinner ARM SoCs
 FEATURES:=ext4 display rootfs-part rtc squashfs usb usbgadget
 SUBTARGETS:=cortexa8 cortexa7 cortexa53
 
-KERNEL_PATCHVER:=6.6
-KERNEL_TESTING_PATCHVER:=6.12
+KERNEL_PATCHVER:=6.12
 
 KERNELNAME:=zImage dtbs