Verdex: Add support for Gumstix Verdex boards.

Gumstix Verdex is a PXA270-based series of computer-on-modules. This
configuration file is based off the voipac.cfg configuration with
a different flash memory configuration. This has been tested flyswatter
adapter to reflash a Gumstix Verdex XL6P board.

tcl/board/verdex.cfg

+# Config for Gumstix Verdex XM4 and XL6P (PXA270)
+
+set CHIPNAME verdex
+source [find target/pxa270.cfg]
+
+# The board supports separate reset lines
+# Override this in the interface config for parallel dongles
+reset_config trst_and_srst separate
+
+# XM4 = 400MHz, XL6P = 600MHz...let's run at 0.1*400MHz=40MHz
+adapter_khz 40000
+
+# flash bank <driver> <base> <size> <chip_width> <bus_width>
+# XL6P has 32 MB flash
+flash bank $_CHIPNAME.flash0 cfi 0x00000000 0x02000000 2 2 $_TARGETNAME
+# XM4 has 16 MB flash
+#flash bank $_CHIPNAME.flash0 cfi 0x00000000 0x01000000 2 2 $_TARGETNAME