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/Rattler.h b/include/configs/Rattler.h
index 587b42e..8140ae9 100644
--- a/include/configs/Rattler.h
+++ b/include/configs/Rattler.h
@@ -33,6 +33,8 @@
 #define CPU_ID_STR		"MPC8250"
 #endif /* CONFIG_MPC8248 */
 
+#define	CONFIG_SYS_TEXT_BASE	0xFE000000
+
 #define CONFIG_CPM2		1	/* Has a CPM2 */
 
 #define CONFIG_RATTLER			/* Analogue&Micro Rattler board */