post: Migrate to Kconfig

We move the existing CONFIG_POST_* functionality over to CFG_POST and
then introduce CONFIG_POST to Kconfig.

Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/post/lib_powerpc/fpu/fpu.c b/post/lib_powerpc/fpu/fpu.c
index bd65f62..8993b36 100644
--- a/post/lib_powerpc/fpu/fpu.c
+++ b/post/lib_powerpc/fpu/fpu.c
@@ -21,7 +21,7 @@
 
 GNU_FPOST_ATTR
 
-#if CONFIG_POST & CONFIG_SYS_POST_FPU
+#if CFG_POST & CONFIG_SYS_POST_FPU
 
 #include <watchdog.h>
 
@@ -71,4 +71,4 @@
 	return ret;
 }
 
-#endif /* CONFIG_POST & CONFIG_SYS_POST_FPU */
+#endif /* CFG_POST & CONFIG_SYS_POST_FPU */