ath79: use kernel 6.1 as default

Signed-off-by: David Bauer <[email protected]>

target/linux/ath79/Makefile

@@ -8,7 +8,7 @@ SUBTARGETS:=generic mikrotik nand tiny
 
 FEATURES:=ramdisk squashfs usbgadget
 
-KERNEL_PATCHVER:=5.15
+KERNEL_PATCHVER:=6.1
 KERNEL_TESTING_PATCHVER:=6.1
 
 include $(INCLUDE_DIR)/target.mk