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/AMX860.h b/include/configs/AMX860.h
index 6e2907e..095c7f0 100644
--- a/include/configs/AMX860.h
+++ b/include/configs/AMX860.h
@@ -36,6 +36,8 @@
 #define CONFIG_MPC860		1
 #define CONFIG_AMX860		1
 
+#define	CONFIG_SYS_TEXT_BASE	0x40000000
+
 #undef	CONFIG_8xx_CONS_SMC1		/* Console is on SCC2		*/
 #undef	CONFIG_8xx_CONS_SMC2
 #define	CONFIG_8xx_CONS_SCC2	1