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/ML2.h b/include/configs/ML2.h
index 2fc0119..8f56902 100644
--- a/include/configs/ML2.h
+++ b/include/configs/ML2.h
@@ -30,6 +30,7 @@
 #define CONFIG_4xx		1	/* ...member of PPC4xx family   */
 #define CONFIG_ML2	1	/* ...on a ML2 board	*/
 
+#define	CONFIG_SYS_TEXT_BASE	0x18000000
 
 #define CONFIG_ENV_IS_IN_FLASH     1