membuff: Rename the files to membuf

Rename the C and header files to use the membuf basename, to match the
functions.

Add a MAINTAINERS entry while we are here.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/lib/Makefile b/lib/Makefile
index a30ce15..41de267 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -125,7 +125,7 @@
 obj-y += linux_compat.o
 obj-y += linux_string.o
 obj-$(CONFIG_$(PHASE_)LMB) += lmb.o
-obj-y += membuff.o
+obj-y += membuf.o
 obj-$(CONFIG_REGEX) += slre.o
 obj-y += string.o
 obj-y += tables_csum.o
diff --git a/lib/membuff.c b/lib/membuf.c
similarity index 99%
rename from lib/membuff.c
rename to lib/membuf.c
index 435d12b..5473efa 100644
--- a/lib/membuff.c
+++ b/lib/membuf.c
@@ -9,7 +9,7 @@
 #include <errno.h>
 #include <log.h>
 #include <malloc.h>
-#include "membuff.h"
+#include "membuf.h"
 
 void membuf_purge(struct membuff *mb)
 {