soc/amd/picasso/config: add comment about cfg never being NULL

Change-Id: I39cf2d28749536cb7d9462fa4af412850677f2e3
Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/48354
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Marshall Dawson <marshalldawson3rd@gmail.com>

src/soc/amd/picasso/config.c

@@ -6,6 +6,7 @@
 
 const struct soc_amd_common_config *soc_get_common_config()
 {
+	/* config_of_soc calls die() internally if cfg was NULL, so no need to re-check */
 	const struct soc_amd_picasso_config *cfg = config_of_soc();
 	return &cfg->common_config;
 }