kbuild: fix scripts/setlocalversion with git

When using trees like wireless-testing, which have untagged tags,
scripts/setlocalversion does not display any git indication for
localversion.

This patch fixes it: If git is available, but no usable tag is found,
it uses -g${head}. It skips the detection of unanottated tags via
git name-rev.

Signed-off-by: Nico Schottelius <nico@ikn.schottelius.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

scripts/setlocalversion

@@ -10,13 +10,12 @@ cd "${1:-.}" || usage
 
 # Check for git and a git repo.
 if head=`git rev-parse --verify --short HEAD 2>/dev/null`; then
-	# Do we have an untagged version?
-	if git name-rev --tags HEAD | grep -E '^HEAD[[:space:]]+(.*~[0-9]*|undefined)$' > /dev/null; then
-		if tag=`git describe 2>/dev/null`; then
-			echo $tag | awk -F- '{printf("-%05d-%s", $(NF-1),$(NF))}'
-		else
-			printf '%s%s' -g $head
-		fi
+	# Do we have an untagged tag?
+	if atag=`git describe 2>/dev/null`; then
+		echo "$atag" | awk -F- '{printf("-%05d-%s", $(NF-1),$(NF))}'
+	# add -g${head}, if there is no usable tag
+	else
+		printf '%s%s' -g $head
 	fi
 
 	# Is this git on svn?