openocd: fix doxygen parameters of functions

Add to doxygen comment the missing parameters.
Remove from doxygen comment any non-existing parameter.
Fix the parameter names in doxygen comment to match the one in the
function prototype.
Where the parameter name in the doxygen description seems better
than the one in the code, change the code.
Escape the character '<' to prevent doxygen to interpret it as an
xml tag.

Change-Id: I22da723339ac7d7a7a64ac4c1cc4336e2416c2cc
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: http://openocd.zylin.com/6002
Tested-by: jenkins

src/target/arc.c

@@ -924,6 +924,7 @@ exit:
  * Finds an actionpoint that triggered last actionpoint event, as specified by
  * DEBUG.ASR.
  *
+ * @param target
  * @param actionpoint Pointer to be set to last active actionpoint. Pointer
  *                    will be set to NULL if DEBUG.AH is 0.
  */