Update MCUBOOT to 4f80913

Signed-off-by: Xinyu Zhang <xinyu.zhang@arm.com>
Change-Id: Icb1af791a570b96e478e62b5032eed6e085d0dcc
diff --git a/tf-m-build-docs.yaml b/tf-m-build-docs.yaml
index 9429241..717e0fb 100644
--- a/tf-m-build-docs.yaml
+++ b/tf-m-build-docs.yaml
@@ -65,7 +65,7 @@
           default: 'https://git.trustedfirmware.org/mirror/mbed-tls.git'
       - string:
           name: 'MCUBOOT_REFSPEC'
-          default: 'fbeef9b94485dd86fbeec4ee7192f58c8c34edb6'
+          default: '4f8091318b4026d14af9e5a7036825bff62fb612'
           description: |
             Specify which MCUboot version to use
             refs/heads/master    : Pick up latest master