staging: clean up Greg's email address in some TODO files

My old email address was in some TODO files, so this fixes that issue.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/et131x/README

@@ -11,6 +11,6 @@ TODO:
 	- Use of kmem_cache seems a bit unusual
 
 Please send patches to:
-	Greg Kroah-Hartman <gregkh@suse.de>
+	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
 	Mark Einon <mark.einon@gmail.com>
 

drivers/staging/keucr/TODO

@@ -9,4 +9,4 @@ TODO:
 	- smcommon.h & smilsub.c: use kernel hweight8(), hweight16()
 
 Please send any patches for this driver to Al Cho <acho@novell.com> and
-Greg Kroah-Hartman <gregkh@suse.de>.
+Greg Kroah-Hartman <gregkh@linuxfoundation.org>.

drivers/staging/slicoss/README

@@ -42,7 +42,7 @@ TODO:
 
 
 Please send patches to:
-        Greg Kroah-Hartman <gregkh@suse.de>
+        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
 and Cc: Lior Dotan <liodot@gmail.com> and Christopher Harrer
 <charrer@alacritech.com> as well as they are also able to test out any
 changes.