perf tools: Really install manpages via 'make install-man'

Target install-man builds them but forget to install.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Borislav Petkov <borislav.petkov@amd.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Fixes: af3df2cf ("perf tools: Try to build Documentation when installing")
Link: http://lkml.kernel.org/r/150322915300.129715.13645857235229756834.stgit@buzzSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Documentation/Makefile

@@ -192,7 +192,7 @@ do-install-man: man
 #		$(INSTALL) -m 644 $(DOC_MAN5) $(DESTDIR)$(man5dir); \
 #		$(INSTALL) -m 644 $(DOC_MAN7) $(DESTDIR)$(man7dir)
 
-install-man: check-man-tools man
+install-man: check-man-tools man do-install-man
 
 ifdef missing_tools
   DO_INSTALL_MAN = $(warning Please install $(missing_tools) to have the man pages installed)