Add cli_ prefix to readline functions

This makes it clear where the code resides.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/common/cmd_mem.c b/common/cmd_mem.c
index 4b8738b..15a4b84 100644
--- a/common/cmd_mem.c
+++ b/common/cmd_mem.c
@@ -1150,7 +1150,7 @@
 		else
 			printf(" %02x", *((u8 *)ptr));
 
-		nbytes = readline (" ? ");
+		nbytes = cli_readline(" ? ");
 		if (nbytes == 0 || (nbytes == 1 && console_buffer[0] == '-')) {
 			/* <CR> pressed as only input, don't modify current
 			 * location and move to next. "-" pressed will go back.