u-boot-mvebu: bump to 2019.04

Some devices and packages require newer version of u-boot to work
properly, update u-boot to keep up with 4.19 kernel.

Signed-off-by: Vladimir Vid <vladimir.vid@sartura.hr>
[re-added missing commit message]
Signed-off-by: Petr Štetiar <ynezz@true.cz>

package/boot/uboot-mvebu/Makefile

@@ -8,10 +8,10 @@
 include $(TOPDIR)/rules.mk
 include $(INCLUDE_DIR)/kernel.mk
 
-PKG_VERSION:=2018.03
+PKG_VERSION:=2019.04
 PKG_RELEASE:=1
 
-PKG_HASH:=7e7477534409d5368eb1371ffde6820f0f79780a1a1f676161c48442cb303dfd
+PKG_HASH:=76b7772d156b3ddd7644c8a1736081e55b78828537ff714065d21dbade229bef
 
 include $(INCLUDE_DIR)/u-boot.mk
 include $(INCLUDE_DIR)/package.mk