armvirt: switch to kernel 6.1

The EFI implementation changes have only been applied
to 6.1, so switch armvirt over to it.

Signed-off-by: Mathew McBride <[email protected]>

target/linux/armvirt/Makefile

@@ -9,8 +9,7 @@ BOARDNAME:=QEMU ARM Virtual Machine
 FEATURES:=fpu pci pcie rtc usb boot-part rootfs-part
 FEATURES+=cpiogz ext4 ramdisk squashfs targz vmdk
 
-KERNEL_PATCHVER:=5.15
-KERNEL_TESTING_PATCHVER:=6.1
+KERNEL_PATCHVER:=6.1
 
 include $(INCLUDE_DIR)/target.mk