loongarch64: switch to Linux 6.12 by default

Use Linux kernel version 6.12 by default for loongarch64 target.

Signed-off-by: Weijie Gao <[email protected]>
Link: https://github.com/openwrt/openwrt/pull/19980
Signed-off-by: Hauke Mehrtens <[email protected]>

target/linux/loongarch64/Makefile

@@ -10,8 +10,7 @@ BOARDNAME:=Loongson LoongArch
 FEATURES:=audio display ext4 pcie boot-part rootfs-part rtc usb targz
 SUBTARGETS:=generic
 
-KERNEL_PATCHVER:=6.6
-KERNEL_TESTING_PATCHVER:=6.12
+KERNEL_PATCHVER:=6.12
 
 KERNELNAME:=vmlinuz.efi dtbs