cmd: cat: add new command

Add cat command to print file content to standard out

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Roger Knecht <rknecht@pm.me>
diff --git a/MAINTAINERS b/MAINTAINERS
index 3377866..1c9939e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -786,6 +786,11 @@
 S:	Maintained
 F:	tools/buildman/
 
+CAT
+M:	Roger Knecht <rknecht@pm.me>
+S:	Maintained
+F:	cmd/cat.c
+
 CFI FLASH
 M:	Stefan Roese <sr@denx.de>
 S:	Maintained