Add entry for kernel 5.10

BUG=b/173821368
TEST=repo sync
RELEASE_NOTE=None

Change-Id: I2bfb36ff5988797ef696da6751124a907f4a642b
Reviewed-on: https://cos-review.googlesource.com/c/cos/manifest/+/14110
Tested-by: Oleksandr Tymoshenko <ovt@google.com>
Reviewed-by: Robert Kolchmeyer <rkolchmeyer@google.com>
diff --git a/external_full.xml b/external_full.xml
index fdd602d..18439e7 100644
--- a/external_full.xml
+++ b/external_full.xml
@@ -96,6 +96,9 @@
   <project path="src/third_party/kernel/v5.4"
            name="third_party/kernel"
            revision="refs/heads/cos-5.4" />
+  <project path="src/third_party/kernel/v5.10"
+           name="third_party/kernel"
+           revision="refs/heads/cos-5.10" />
 
   <repo-hooks enabled-list="pre-upload"
            in-project="cos/repohooks" />