common/xyzModem.c: move empty statements to newline

To prevent a warning for clang the loop without a body
is made more clear by moving it to a line of its own.
This prevents a clang warning.

cc: sbabic@denx.de
Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>
diff --git a/common/xyzModem.c b/common/xyzModem.c
index 39f7d17..56f4bca 100644
--- a/common/xyzModem.c
+++ b/common/xyzModem.c
@@ -759,7 +759,8 @@
        * If we don't eat it now, RedBoot will think the user typed it.
        */
       ZM_DEBUG (zm_dprintf ("Trailing gunk:\n"));
-      while ((c = (*getc) ()) > -1);
+      while ((c = (*getc) ()) > -1)
+        ;
       ZM_DEBUG (zm_dprintf ("\n"));
       /*
        * Make a small delay to give terminal programs like minicom