tcl: board: ti_am43xx_evm: follow xds100v2 requirements

xds100v2 asks us to call these three commands to
guarantee proper behavior, so do it.

Change-Id: Iecf9c148ce7c2082ef915b46eeb511ceea395cc3
Signed-off-by: Felipe Balbi <balbi@ti.com>
Reviewed-on: http://openocd.zylin.com/2613
Tested-by: jenkins
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Paul Fertser <fercerpav@gmail.com>

tcl/board/ti_am43xx_evm.cfg

@@ -9,3 +9,7 @@ adapter_khz 16000
 source [find target/am437x.cfg]
 
 reset_config trst_and_srst
+
+init
+ftdi_set_signal PWR_RST 1
+jtag arp_init