ipq807x: switch to kernel 6.1

Now that 6.1 kernel is working fine on ipq807x , lets switch to 6.1 as the
default kernel as its increasingly hard to keep backporting upstreamed
changes to 5.15.

Signed-off-by: Robert Marko <[email protected]>

target/linux/ipq807x/Makefile

@@ -8,8 +8,7 @@ KERNELNAME:=Image dtbs
 CPU_TYPE:=cortex-a53
 SUBTARGETS:=generic
 
-KERNEL_PATCHVER:=5.15
-KERNEL_TESTING_PATCHVER:=6.1
+KERNEL_PATCHVER:=6.1
 
 include $(INCLUDE_DIR)/target.mk
 DEFAULT_PACKAGES += \