rtla: Follow kernel version

To avoid having commits with new version, it is just easier to follow
kernel version.

Link: https://lkml.kernel.org/r/9c2df0d1de65cea96c7d731fe64781a2bb90c5b3.1643990447.git.bristot@kernel.org

Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: linux-kernel@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Author: Daniel Bristot de Oliveira

tools/tracing/rtla/Makefile

@@ -1,5 +1,6 @@
 NAME	:=	rtla
-VERSION	:=	0.5
+# Follow the kernel version
+VERSION :=	$(shell cat VERSION 2> /dev/null || make -sC ../../.. kernelversion)
 
 # From libtracefs:
 # Makefiles suck: This macro sets a default value of $(2) for the
@@ -85,6 +86,7 @@ clean: doc_clean
 
 tarball: clean
 	rm -rf $(NAME)-$(VERSION) && mkdir $(NAME)-$(VERSION)
+	echo $(VERSION) > $(NAME)-$(VERSION)/VERSION
 	cp -r $(DIRS) $(FILES) $(NAME)-$(VERSION)
 	mkdir $(NAME)-$(VERSION)/Documentation/
 	cp -rp $(SRCTREE)/../../../Documentation/tools/rtla/* $(NAME)-$(VERSION)/Documentation/