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/ZPC1900.h b/include/configs/ZPC1900.h
index d0dc067..d305fa4 100644
--- a/include/configs/ZPC1900.h
+++ b/include/configs/ZPC1900.h
@@ -29,6 +29,9 @@
 
 #define CONFIG_MPC8260		1	/* This is an MPC8260 CPU      */
 #define CONFIG_ZPC1900		1	/* ...on Zephyr ZPC.1900 board */
+
+#define	CONFIG_SYS_TEXT_BASE	0xFE000000
+
 #define CPU_ID_STR		"MPC8265"
 #define CONFIG_CPM2		1	/* Has a CPM2 */