Program loading: Handoff cbmem_top via calling arguments

There are a lot of different implementations to pass information from
romstage to ramstage. These could all be unified by passing this
information via cbmem. Often however these methods exist for that very
purpose. This solves this by passing cbmem_top via the programs
arguments.

Change-Id: Id2031f7bb81ce65fc318313c270eb1fbae3b2114
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/36272
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/include/program_loading.h

@@ -137,6 +137,11 @@ static inline void prog_set_entry(struct prog *prog, void *e, void *arg)
 	prog->arg = arg;
 }
 
+static inline void prog_set_arg(struct prog *prog, void *arg)
+{
+	prog->arg = arg;
+}
+
 /* Locate the identified program to run. Return 0 on success. < 0 on error. */
 int prog_locate(struct prog *prog);
 /* The prog_locate_hook() is called prior to CBFS traversal. The hook can be