Makefile: move all Power Architecture boards into boards.cfg

Clean up Makefile, and drop a lot of the config.mk files on the way.

We now also automatically pick all boards that are listed in
boards.cfg (and with all configurations), so we can drop the redundant
entries from MAKEALL to avoid building these twice.

Signed-off-by: Wolfgang Denk <wd@denx.de>
diff --git a/include/configs/RBC823.h b/include/configs/RBC823.h
index 00ac6cf..471f32e 100644
--- a/include/configs/RBC823.h
+++ b/include/configs/RBC823.h
@@ -39,6 +39,7 @@
 #define CONFIG_MPC823		1	/* This is a MPC823 CPU		*/
 #define CONFIG_RBC823		1	/* ...on a RBC823 module	*/
 
+#define	CONFIG_SYS_TEXT_BASE	0xFFF00000
 
 #if 0
 #define DEBUG			1