treewide: fix GPLv2+ obsolete-license warnings

The LICENSE string 'GPLv2+' is considered obsolete by Yocto and raises a
warning.  Switch them too the accepted tag 'GPL-2.0-or-later'.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I88c639dbb45762e2e019a3503f1f1930b65c09d6
diff --git a/meta-aspeed/recipes-bsp/u-boot/u-boot-common-aspeed-sdk_2019.04.inc b/meta-aspeed/recipes-bsp/u-boot/u-boot-common-aspeed-sdk_2019.04.inc
index ae82748..8efeaed 100644
--- a/meta-aspeed/recipes-bsp/u-boot/u-boot-common-aspeed-sdk_2019.04.inc
+++ b/meta-aspeed/recipes-bsp/u-boot/u-boot-common-aspeed-sdk_2019.04.inc
@@ -2,7 +2,7 @@
 SECTION = "bootloaders"
 DEPENDS += "flex-native bison-native xxd-native"
 
-LICENSE = "GPLv2+"
+LICENSE = "GPL-2.0-or-later"
 LIC_FILES_CHKSUM = "file://Licenses/README;md5=30503fd321432fc713238f582193b78e"
 PE = "1"
 
diff --git a/meta-aspeed/recipes-bsp/u-boot/u-boot-common-aspeed_2016.07.inc b/meta-aspeed/recipes-bsp/u-boot/u-boot-common-aspeed_2016.07.inc
index fa6e750..6f8cdf7 100644
--- a/meta-aspeed/recipes-bsp/u-boot/u-boot-common-aspeed_2016.07.inc
+++ b/meta-aspeed/recipes-bsp/u-boot/u-boot-common-aspeed_2016.07.inc
@@ -2,7 +2,7 @@
 SECTION = "bootloaders"
 DEPENDS += "flex-native bison-native"
 
-LICENSE = "GPLv2+"
+LICENSE = "GPL-2.0-or-later"
 LIC_FILES_CHKSUM = "file://Licenses/README;md5=a2c678cfd4a4d97135585cad908541c6"
 PE = "1"