jtag: cut down on usage of unintended modification of global end state

jtag_get/set_end_state() is now deprecated.

There were lots of places in the code where the end state was
unintentionally modified.

The big Q is whether there were any places where the intention
was to modify the end state. 0.5 is a long way off, so we'll
get a fair amount of testing.

Signed-off-by: Øyvind Harboe <oyvind.harboe@zylin.com>

src/jtag/jtag.h

@@ -552,15 +552,18 @@ void jtag_add_reset(int req_tlr_or_trst, int srst);
 
 
 /**
+ * DEPRECATED! store such global state outside JTAG layer
+ *
  * Function jtag_set_end_state
  *
  * Set a global variable to \a state if \a state != TAP_INVALID.
  *
- * Return the value of the global variable.
  */
-tap_state_t jtag_set_end_state(tap_state_t state);
+void jtag_set_end_state(tap_state_t state);
 
 /**
+ * DEPRECATED! store such global state outside JTAG layer
+ * 
  * Function jtag_get_end_state
  *
  * Return the value of the global variable for end state