tcl at91samdXX.cfg: update config to current OpenOCD status

Remove comment about workaround of not working 'reset halt' - not needed
as 'reset halt' is working as expected @ EDBG with srst_only.
Add srst_pulls_trst to reset_config as it no more triggers an error.

Change-Id: I47cf445690c46ccfb866900cddbfcaefc8649f82
Signed-off-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-on: http://openocd.zylin.com/3722
Tested-by: jenkins
Reviewed-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>

tcl/target/at91samdXX.cfg

@@ -50,13 +50,7 @@ $_TARGETNAME configure -event reset-deassert-post {
 }
 
 # SRST (wired to RESET_N) resets debug circuitry
-# srst_pulls_trst is not configured here to avoid an error raised in reset halt
-reset_config srst_gates_jtag
-
-# Atmel's EDBG (on-board cmsis-dap adapter of Xplained kits) cannot
-# stop the MCU before it starts executing code if hardware RESETN
-# line is configured by command "reset_config srst_only"
-# Use "reset_config none" (default) before flash programming.
+reset_config srst_gates_jtag srst_pulls_trst
 
 # Do not use a reset button with other SWD adapter than Atmel's EDBG.
 # DSU usually locks MCU in reset state until you issue a reset command