MIPS: Move Cobalt Makefile parts to their own Platform file

Signed-off-by: Yoichi Yuasa <yuasa@linux-mips.org>
Cc: linux-mips <linux-mips@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/1321/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/Kbuild.platforms b/arch/mips/Kbuild.platforms
index 77e48b9..6c163c2 100644
--- a/arch/mips/Kbuild.platforms
+++ b/arch/mips/Kbuild.platforms
@@ -2,6 +2,7 @@
 
 platforms += alchemy
 platforms += ar7
+platforms += cobalt
 platforms += loongson
 platforms += mipssim
 platforms += sgi-ip27