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/PM520.h b/include/configs/PM520.h
index 957bf22..e1e709f 100644
--- a/include/configs/PM520.h
+++ b/include/configs/PM520.h
@@ -33,6 +33,8 @@
 #define CONFIG_MPC5xxx		1	/* This is an MPC5xxx CPU */
 #define CONFIG_PM520		1	/* ... on PM520 board */
 
+#define	CONFIG_SYS_TEXT_BASE	0xfff00000
+
 #define CONFIG_SYS_MPC5XXX_CLKIN	33000000 /* ... running at 33MHz */
 
 #define CONFIG_MISC_INIT_R