powerpc/5200: Add support for the Media5200 board from Freescale

This patch adds board support for the Media5200 platform.  Changes are:
- add the media5200 device tree
- add the media5200 platform support code and cascaded interrupt controller
- add media5200 to the build targets.

Note: this patch also includes a minor tweak to the lite5200(b) target
images list to add the .dtb files to the image list.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/arch/powerpc/boot/Makefile b/arch/powerpc/boot/Makefile
index e84df33..8244813 100644
--- a/arch/powerpc/boot/Makefile
+++ b/arch/powerpc/boot/Makefile
@@ -235,7 +235,9 @@
 					   dtbImage.adder875-redboot
 
 # Board ports in arch/powerpc/platform/52xx/Kconfig
-image-$(CONFIG_PPC_LITE5200)		+= cuImage.lite5200 cuImage.lite5200b
+image-$(CONFIG_PPC_LITE5200)		+= cuImage.lite5200 lite5200.dtb
+image-$(CONFIG_PPC_LITE5200)		+= cuImage.lite5200b lite5200b.dtb
+image-$(CONFIG_PPC_MEDIA5200)		+= cuImage.media5200 media5200.dtb
 
 # Board ports in arch/powerpc/platform/82xx/Kconfig
 image-$(CONFIG_MPC8272_ADS)		+= cuImage.mpc8272ads