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/walnut.h b/include/configs/walnut.h
index 3be489d..72ac4e3 100644
--- a/include/configs/walnut.h
+++ b/include/configs/walnut.h
@@ -36,7 +36,9 @@
 #define CONFIG_405GP		1	/* This is a PPC405 CPU		*/
 #define CONFIG_4xx		1	/* ...member of PPC4xx family	*/
 #define CONFIG_WALNUT		1	/* ...on a WALNUT board		*/
-					/* ...and on a SYCAMORE board	*/
+					/* ...or on a SYCAMORE board	*/
+
+#define	CONFIG_SYS_TEXT_BASE	0xFFFC0000
 
 /*
  * Include common defines/options for all AMCC eval boards