linux-aspeed: Move to 4.19.21

This includes security and bug fixes from the 4.19.20 and
4.19.21 stable releases.

Change-Id: I1e8d1de8076635ff8b873b9064764448a00662dd
Signed-off-by: Joel Stanley <joel@jms.id.au>
diff --git a/recipes-kernel/linux/linux-aspeed_git.bb b/recipes-kernel/linux/linux-aspeed_git.bb
index 9640c9c..e27482b 100644
--- a/recipes-kernel/linux/linux-aspeed_git.bb
+++ b/recipes-kernel/linux/linux-aspeed_git.bb
@@ -1,6 +1,6 @@
 KBRANCH ?= "dev-4.19"
-LINUX_VERSION ?= "4.19.19"
+LINUX_VERSION ?= "4.19.21"
 
-SRCREV="3931734021a55283294733ce514803842833d2f4"
+SRCREV="d808d27f70f7d4158151534ed0a28ab7dae62b8d"
 
 require linux-aspeed.inc