apm821xx: switch to 4.14.x kernel

Signed-off-by: Christian Lamparter <[email protected]>

target/linux/apm821xx/Makefile

@@ -13,7 +13,7 @@ MAINTAINER:=Chris Blake <[email protected]>, \
 	    Christian Lamparter <[email protected]>
 SUBTARGETS:=nand sata
 
-KERNEL_PATCHVER:=4.9
+KERNEL_PATCHVER:=4.14
 
 define Target/Description
 	Build images for AppliedMicro APM821xx based boards.