target/imx6sx: Initial support

Unlike the rest of imx6 a Cortex-M4 was added with a second CoreSight
DAP so a separate script is required.

Tested on imx6sx-sdb running linux

Change-Id: I1561910b233015f42508f341175822c0827655ec
Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
Reviewed-on: http://openocd.zylin.com/5041
Tested-by: jenkins
Reviewed-by: Matthias Welwarsky <matthias@welwarsky.de>

tcl/target/imx6sx.cfg

@@ -0,0 +1,50 @@
+#
+# Freescale i.MX6SoloX
+#
+
+if { [info exists CHIPNAME] } {
+    set _CHIPNAME $CHIPNAME
+} else {
+    set _CHIPNAME imx6sx
+}
+
+# 2x CoreSight Debug Access Port for Cortex-M4 and Cortex-A9
+if { [info exists DAP_TAPID] } {
+    set _DAP_TAPID $DAP_TAPID
+} else {
+    set _DAP_TAPID 0x4ba00477
+}
+
+jtag newtap $_CHIPNAME cpu_m4 -irlen 4 -ircapture 0x01 -irmask 0x0f \
+        -expected-id $_DAP_TAPID
+dap create $_CHIPNAME.dap_m4 -chain-position $_CHIPNAME.cpu_m4
+
+jtag newtap $_CHIPNAME cpu_a9 -irlen 4 -ircapture 0x01 -irmask 0x0f \
+        -expected-id $_DAP_TAPID
+dap create $_CHIPNAME.dap_a9 -chain-position $_CHIPNAME.cpu_a9
+
+# SDMA / no IDCODE
+jtag newtap $_CHIPNAME sdma -irlen 4 -ircapture 0x00 -irmask 0x0f
+
+# System JTAG Controller
+if { [info exists SJC_TAPID] } {
+    set _SJC_TAPID $SJC_TAPID
+} else {
+    set _SJC_TAPID 0x0891c01d
+}
+jtag newtap $_CHIPNAME sjc -irlen 5 -ircapture 0x01 -irmask 0x1f \
+        -expected-id $_SJC_TAPID -ignore-version
+
+# Cortex-A9 (boot core)
+target create $_CHIPNAME.cpu_a9 cortex_a -dap $_CHIPNAME.dap_a9 \
+        -coreid 0 -dbgbase 0x82150000
+
+# Cortex-M4 (default off)
+target create $_CHIPNAME.cpu_m4 cortex_m -dap $_CHIPNAME.dap_m4 \
+        -ap-num 0 -defer-examine
+
+# AHB mem-ap target
+target create $_CHIPNAME.ahb mem_ap -dap $_CHIPNAME.dap_a9 -ap-num 0
+
+# Default target is Cortex-A9
+targets $_CHIPNAME.cpu_a9