board: introduce base config for TI BeagleBone family boards

This patch adds the file ti_beaglebone-base.cfg as the common base
configuration for all TI BeagleBone derived boards. It also modifies
ti_beaglebone.cfg to source the base board and only add the on-board
JTAG adapter. Lastly, it adds a file ti_beaglebone_black.cfg with
a suitable configuraton for the BeagleBone "Black" variant.

Change-Id: I40cacb8abed7bdb308929713891f7b5e5b685c95
Signed-off-by: Matthias Welwarsky <matthias@welwarsky.de>
Reviewed-on: http://openocd.zylin.com/3099


Tested-by: jenkins
Reviewed-by: Freddie Chopin <freddie.chopin@gmail.com>

tcl/board/ti_beaglebone-base.cfg

+# AM335x Beaglebone family base configuration
+#  http://beagleboard.org/bone
+
+source [find target/am335x.cfg]

tcl/board/ti_beaglebone.cfg

@@ -6,8 +6,8 @@ source [find interface/ftdi/xds100v2.cfg]
 
 adapter_khz 16000
 
-source [find target/am335x.cfg]
-
 reset_config trst_and_srst
 
+source [find board/ti_beaglebone-base.cfg]
+
 

tcl/board/ti_beaglebone_black.cfg

+# AM335x Beaglebone Black
+#  http://beagleboard.org/bone
+
+adapter_khz 1000
+
+reset_config trst_and_srst
+
+source [find board/ti_beaglebone-base.cfg]