tools lib traceevent: Add do_install_mkdir Makefile function

Decompose the do_install function to ease up
the following patch a little.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/n/tip-zzs19yx8seyors532vuer37w@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/lib/traceevent/Makefile

@@ -236,10 +236,14 @@ TAGS:	force
 	find . -name '*.[ch]' | xargs etags \
 	--regex='/_PE(\([^,)]*\).*/PEVENT_ERRNO__\1/'
 
+define do_install_mkdir
+	if [ ! -d '$(DESTDIR_SQ)$1' ]; then		\
+		$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$1';	\
+	fi
+endef
+
 define do_install
-	if [ ! -d '$(DESTDIR_SQ)$2' ]; then		\
-		$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$2';	\
-	fi;						\
+	$(call do_install_mkdir,$2);			\
 	$(INSTALL) $(if $3,-m $3,) $1 '$(DESTDIR_SQ)$2'
 endef