cbmem: Make cbmem_online() accurate on stages after romstage

cbmem_online() always returns 1 in stages after romstage. However, CBMEM
isn't actually immediately available in those stages -- instead, it will
only become available when cbmem_initialize() is called. That usually
happens very early in the stage, but there are still small amounts of
code running beforehand, so it is useful to reflect this distinction.

Signed-off-by: Julius Werner <jwerner@chromium.org>
Change-Id: I623c0606a4f49ea98c4c7559436bf32ebb83b456
Reviewed-on: https://review.coreboot.org/c/coreboot/+/48428
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>

src/include/cbmem.h

@@ -163,10 +163,7 @@ static inline int cbmem_online(void)
 	if (!cbmem_possibly_online())
 		return 0;
 
-	if (ENV_ROMSTAGE)
-		return cbmem_initialized;
-
-	return 1;
+	return cbmem_initialized;
 }
 
 #endif /* _CBMEM_H_ */