Only show bootsplash during boot menu.

When the bootsplash picture is shown, it's not possible to see text.
So, only display the picture while prompting the user for the boot
menu.
diff --git a/src/boot.c b/src/boot.c
index 44964a7..021b8ac 100644
--- a/src/boot.c
+++ b/src/boot.c
@@ -227,7 +227,9 @@
 
     printf("Press F12 for boot menu.\n\n");
 
+    enable_bootsplash();
     int scan_code = get_keystroke(CONFIG_BOOTMENU_WAIT);
+    disable_bootsplash();
     if (scan_code != 0x86)
         /* not F12 */
         return;
@@ -343,9 +345,6 @@
 static void
 call_boot_entry(u16 bootseg, u16 bootip, u8 bootdrv)
 {
-    /* Go back to text, the OS might expect it... (Can't do this any later) */
-    disable_bootsplash();
-
     dprintf(1, "Booting from %04x:%04x\n", bootseg, bootip);
     struct bregs br;
     memset(&br, 0, sizeof(br));
@@ -430,7 +429,6 @@
             return;
         if (count--)
             continue;
-        disable_bootsplash();
         cbfs_run_payload(file);
     }
 }