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/mecp5123.h b/include/configs/mecp5123.h
index fe32bb2..43c0528 100644
--- a/include/configs/mecp5123.h
+++ b/include/configs/mecp5123.h
@@ -48,6 +48,8 @@
 #define CONFIG_E300		1	/* E300 Family */
 #define CONFIG_MPC512X		1	/* MPC512X family */
 
+#define	CONFIG_SYS_TEXT_BASE	0xFFF00000
+
 #define CONFIG_SYS_MPC512X_CLKIN	33333333	/* in Hz */
 
 #define CONFIG_BOARD_EARLY_INIT_F		/* call board_early_init_f() */