kbuild: link-vmlinux.sh: simplify .version increment

Since commit 1f2bfbd00e46 ("kbuild: link of vmlinux moved to a
script"), it is easy to increment .version without using a temporary
file .old_version.

I do not see anybody who creates the .tmp_version.  Probably it is a
left-over of commit 4e25d8bb9550fb ("[PATCH] kbuild: adjust .version
updating").  Just remove it.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index e7b7eee..0cdb25b 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -187,10 +187,8 @@
 # Delete output files in case of error
 cleanup()
 {
-	rm -f .old_version
 	rm -f .tmp_System.map
 	rm -f .tmp_kallsyms*
-	rm -f .tmp_version
 	rm -f .tmp_vmlinux*
 	rm -f built-in.o
 	rm -f System.map
@@ -238,12 +236,12 @@
 
 # Update version
 info GEN .version
-if [ ! -r .version ]; then
-	rm -f .version;
-	echo 1 >.version;
+if [ -r .version ]; then
+	VERSION=$(expr 0$(cat .version) + 1)
+	echo $VERSION > .version
 else
-	mv .version .old_version;
-	expr 0$(cat .old_version) + 1 >.version;
+	rm -f .version
+	echo 1 > .version
 fi;
 
 # final build of init/
@@ -331,6 +329,3 @@
 		exit 1
 	fi
 fi
-
-# We made a new kernel - delete old version file
-rm -f .old_version