POST: add progress API

Add POST progress API implemented as weak calls before and after
each call to the POST test callback in the post_run_single routine
of the post.c file.

Signed-off-by: Michael Zaidman <michael.zaidman@gmail.com>
Acked-by: Detlev Zundel <dzu@denx.de>

include/post.h

@@ -53,6 +53,11 @@
 
 #define POST_FAIL_SAVE		0x80
 
+#define POST_BEFORE		1
+#define POST_AFTER		0
+#define POST_PASSED		1
+#define POST_FAILED		0
+
 #ifndef	__ASSEMBLY__
 
 struct post_test {