membuf: Rename struct

Rename the struct to match the function prefix and filenames.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/include/asm-generic/global_data.h b/include/asm-generic/global_data.h
index 18d9459..506ee51 100644
--- a/include/asm-generic/global_data.h
+++ b/include/asm-generic/global_data.h
@@ -316,14 +316,14 @@
 	 *
 	 * This buffer is used to collect output during console recording.
 	 */
-	struct membuff console_out;
+	struct membuf console_out;
 	/**
 	 * @console_in: input buffer for console recording
 	 *
 	 * If console recording is activated, this buffer can be used to
 	 * emulate input.
 	 */
-	struct membuff console_in;
+	struct membuf console_in;
 #endif
 #if CONFIG_IS_ENABLED(VIDEO)
 	/**