#include "target.h" less wildly

Don't include "target.h" from more headers than necessary.  This
avoids needless interdependencies and duplicated include paths.

Don't needlessly include it in source files, either.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>

src/flash/mflash.h

@@ -20,7 +20,7 @@
 #ifndef _MFLASH_H
 #define _MFLASH_H
 
-#include "target.h"
+struct command_context;
 
 typedef unsigned long mg_io_uint32;
 typedef unsigned short mg_io_uint16;