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/mpc8308_p1m.h b/include/configs/mpc8308_p1m.h
index 33d1844..18f205a 100644
--- a/include/configs/mpc8308_p1m.h
+++ b/include/configs/mpc8308_p1m.h
@@ -33,6 +33,10 @@
 #define CONFIG_MPC8308		1 /* MPC8308 CPU specific */
 #define CONFIG_MPC8308_P1M	1 /* mpc8308_p1m board specific */
 
+#ifndef CONFIG_SYS_TEXT_BASE
+#define CONFIG_SYS_TEXT_BASE	0xFC000000
+#endif
+
 /*
  * On-board devices
  *