metag: minimal TZ1090 (Comet) SoC infrastructure

Add really minimal support for Toumaz Xenif TZ1090 SoC (A.K.A. Comet).
This consists of minimal build infrastructure, device tree files, and a
defconfig based on meta2_defconfig.

This SoC contains a 2-threaded HTP (Meta 2) as the main application
processor, and is found in a number of development boards and digital
radios, such as the Minimorph Development Platform.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Rob Landley <rob@landley.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linux-doc@vger.kernel.org
Cc: devicetree-discuss@lists.ozlabs.org
diff --git a/arch/metag/Makefile b/arch/metag/Makefile
index b566116..9739857 100644
--- a/arch/metag/Makefile
+++ b/arch/metag/Makefile
@@ -20,7 +20,7 @@
 checkflags-$(CONFIG_METAG_META21)	+= -DMETAC_2_1
 CHECKFLAGS				+= -D__metag__ $(checkflags-y)
 
-KBUILD_DEFCONFIG			:= meta2_defconfig
+KBUILD_DEFCONFIG			:= tz1090_defconfig
 
 sflags-$(CONFIG_METAG_META12)		+= -mmetac=1.2
 ifeq ($(CONFIG_METAG_META12),y)