soc/amd/*/northbridge,root_complex: add comment about PCI BARs

Add a comment to point out that the read_resources functions aren't
missing a pci_dev_read_resources call that would add the resources for
the BARs of the PC device.

Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: Ie480832e0d7954135d2171dda986e477ef7b6c09
Reviewed-on: https://review.coreboot.org/c/coreboot/+/62547
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Raul Rangel <rrangel@chromium.org>

src/soc/amd/cezanne/root_complex.c

@@ -114,6 +114,9 @@ static void read_resources(struct device *dev)
 	early_reserved_dram_start = e->base;
 	early_reserved_dram_end = e->base + e->size;
 
+	/* The root complex has no PCI BARs implemented, so there's no need to call
+	   pci_dev_read_resources for it */
+
 	/* 0x0 - 0x9ffff */
 	ram_resource(dev, idx++, 0, 0xa0000 / KiB);
 

src/soc/amd/picasso/root_complex.c

@@ -114,6 +114,9 @@ static void read_resources(struct device *dev)
 	early_reserved_dram_start = e->base;
 	early_reserved_dram_end = e->base + e->size;
 
+	/* The root complex has no PCI BARs implemented, so there's no need to call
+	   pci_dev_read_resources for it */
+
 	/* 0x0 - 0x9ffff */
 	ram_resource(dev, idx++, 0, 0xa0000 / KiB);
 

src/soc/amd/sabrina/root_complex.c

@@ -116,6 +116,9 @@ static void read_resources(struct device *dev)
 	early_reserved_dram_start = e->base;
 	early_reserved_dram_end = e->base + e->size;
 
+	/* The root complex has no PCI BARs implemented, so there's no need to call
+	   pci_dev_read_resources for it */
+
 	/* 0x0 - 0x9ffff */
 	ram_resource(dev, idx++, 0, 0xa0000 / KiB);
 

src/soc/amd/stoneyridge/northbridge.c

@@ -60,6 +60,9 @@ static void read_resources(struct device *dev)
 	unsigned int idx = 0;
 	struct resource *res;
 
+	/* The northbridge has no PCI BARs implemented, so there's no need to call
+	   pci_dev_read_resources for it */
+
 	/*
 	 * This MMCONF resource must be reserved in the PCI domain.
 	 * It is not honored by the coreboot resource allocator if it is in