soc/amd/common/block/i2c: implement proper read_resource

Before this patch the reservation of the MMIO region of the I2C
controllers was done in the LPC controller PCI device despite the I2C
controllers already being devices in the devicetree. This patch
implements this functionality as read_resources function of the I2C
device instead. This will only reserve the memory when the I2C devices
are enabled in devicetree which is a change from the previous behavior.

Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: I67c853df3be2f593ecfa113ae2f74e5df7cf74e0
Reviewed-on: https://review.coreboot.org/c/coreboot/+/58307
Reviewed-by: Raul Rangel <rrangel@chromium.org>
Reviewed-by: Karthik Ramasubramanian <kramasub@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/soc/amd/common/block/i2c/i2c.c b/src/soc/amd/common/block/i2c/i2c.c
index 892c83e..ff9ec90 100644
--- a/src/soc/amd/common/block/i2c/i2c.c
+++ b/src/soc/amd/common/block/i2c/i2c.c
@@ -121,9 +121,13 @@
 	dw_i2c_soc_init(false);
 }
 
+static void i2c_read_resources(struct device *dev)
+{
+	mmio_resource(dev, 0, dev->path.mmio.addr / KiB, 4);
+}
+
 struct device_operations soc_amd_i2c_mmio_ops = {
-	/* TODO(kramasub): Move I2C resource info here. */
-	.read_resources = noop_read_resources,
+	.read_resources = i2c_read_resources,
 	.set_resources = noop_set_resources,
 	.scan_bus = scan_smbus,
 	.acpi_name = i2c_acpi_name,