Minor: Separate UUID display from F12 boot prompt.

Place the extra newline as part of the F12 prompt instead of the
SeaBIOS version banner so that a UUID report (when present) is still
visually separated from the boot menu prompt.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
diff --git a/src/boot.c b/src/boot.c
index 3ca7960..c67cc7f 100644
--- a/src/boot.c
+++ b/src/boot.c
@@ -400,7 +400,7 @@
     while (get_keystroke(0) >= 0)
-    printf("Press F12 for boot menu.\n\n");
+    printf("\nPress F12 for boot menu.\n\n");
     u32 menutime = romfile_loadint("etc/boot-menu-wait", DEFAULT_BOOTMENU_WAIT);