ath79: switch to kernel 5.4

As the reported major bugs are ironed out, switch to the new kernel to
begin testing with a broader audience.

Signed-off-by: David Bauer <mail@david-bauer.net>
Acked-by: Hauke Mehrtens <hauke@hauke-m.de>

target/linux/ath79/Makefile

@@ -8,7 +8,7 @@ SUBTARGETS:=generic mikrotik nand tiny
 
 FEATURES:=ramdisk
 
-KERNEL_PATCHVER:=4.19
+KERNEL_PATCHVER:=5.4
 KERNEL_TESTING_PATCHVER:=5.4
 
 include $(INCLUDE_DIR)/target.mk