baremetal-helloworld: set UPSTREAM_CHECK_COMMITS

set UPSTREAM_CHECK_COMMITS to make new commit is reported

Test result(change SRCREV to an old one):
$devtool check-upgrade-status baremetal-helloworld
baremetal-helloworld      0.1             new commits     Alejandro Hernandez <alejandro@enedino.org> db2bf750eaef7fc0832e13ada8291343bbcc3afe

(From OE-Core rev: 3d7d324ca0ea242f1455332a20ac7b0f3cdcd761)

Signed-off-by: Changqing Li <changqing.li@windriver.com>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-extended/baremetal-example/baremetal-helloworld_git.bb

@@ -8,7 +8,7 @@ SRCREV = "db2bf750eaef7fc0832e13ada8291343bbcc3afe"
 PV = "0.1+git"
 
 SRC_URI = "git://github.com/ahcbb6/baremetal-helloqemu.git;protocol=https;branch=master"
-UPSTREAM_VERSION_UNKNOWN = "1"
+UPSTREAM_CHECK_COMMITS = "1"
 
 # The following variables should be set to accomodate each application
 BAREMETAL_BINNAME ?= "hello_baremetal_${MACHINE}"