bootloader/common: disable unused broken code

Disable (probably old) broken code, this fixes bootloader builds
when ROCKBOX_HAS_LOGF is used.

Change-Id: Id0ed2c3368855e2d2d2dbfb18149b9ed81c10b95
diff --git a/bootloader/common.c b/bootloader/common.c
index 21b26e8..46c0e34 100644
--- a/bootloader/common.c
+++ b/bootloader/common.c
@@ -154,6 +154,8 @@
     return len;
 }
 
+/* FIXME?: unused broken code */
+#if 0
 #ifdef ROCKBOX_HAS_LOGF /* Logf display helper for the bootloader */
 
 #define LINES   (LCD_HEIGHT/SYSFONT_HEIGHT)
@@ -233,3 +235,4 @@
     }
 }
 #endif
+#endif