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/board/avnet/fx12mm/config.mk b/board/avnet/fx12mm/config.mk
index f5a6039..78dde62 100644
--- a/board/avnet/fx12mm/config.mk
+++ b/board/avnet/fx12mm/config.mk
@@ -23,4 +23,7 @@
 #
 #
 
-sinclude $(SRCTREE)/board/xilinx/ppc405-generic/config.mk
+ifdef CONFIG_SYS_LDSCRIPT
+# need to strip off double quotes
+LDSCRIPT := $(subst ",,$(CONFIG_SYS_LDSCRIPT))
+endif