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/MPC837XERDB.h b/include/configs/MPC837XERDB.h
index d69d25e..afc37b5 100644
--- a/include/configs/MPC837XERDB.h
+++ b/include/configs/MPC837XERDB.h
@@ -30,6 +30,8 @@
 #define CONFIG_MPC837x		1 /* MPC837x CPU specific */
 #define CONFIG_MPC837XERDB	1
 
+#define	CONFIG_SYS_TEXT_BASE	0xFE000000
+
 #define CONFIG_PCI	1
 
 #define CONFIG_BOARD_EARLY_INIT_F