patman: Add a call to get_maintainer.pl if it exists

For Linux the best way to figure out where to send a patch is with the
"get_maintainer.pl" script.  Add support for calling it from patman.
Support is added unconditionally for "scripts/get_maintainer.pl" in
case it is helpful for any other projects.

Signed-off-by: Doug Anderson <dianders@chromium.org>
diff --git a/tools/patman/README b/tools/patman/README
index 5b6eba0..16b51eb 100644
--- a/tools/patman/README
+++ b/tools/patman/README
@@ -43,6 +43,9 @@
 
 in one of your commits, the series will be sent there.
 
+In Linux this will also call get_maintainer.pl on each of your
+patches automatically.
+
 
 How to use this tool
 ====================
@@ -65,8 +68,12 @@
 How to configure it
 ===================
 
-For most cases patman will locate and use the file 'doc/git-mailrc' in
-your U-Boot directory. This contains most of the aliases you will need.
+For most cases of using patman for U-Boot developement patman will
+locate and use the file 'doc/git-mailrc' in your U-Boot directory.
+This contains most of the aliases you will need.
+
+For Linux the 'scripts/get_maintainer.pl' handles figuring out where
+to send patches pretty well.
 
 During the first run patman creates a config file for you by taking the default
 user name and email address from the global .gitconfig file.