drivers/spi: Add support for generating SPI device in SSDT

Similar to I2C driver, add support for generating SPI device and
required properties in SSDT for ACPI.

BUG=chrome-os-partner:59832
BRANCH=None
TEST=Compiles succesfully. Verified SPI device generated in SSDT on
poppy.

Change-Id: Ic4da79c823131d54d9eb3652b86f6e40fe643ab5
Signed-off-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: https://review.coreboot.org/18342
Tested-by: build bot (Jenkins)
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
diff --git a/src/drivers/spi/acpi/chip.h b/src/drivers/spi/acpi/chip.h
new file mode 100644
index 0000000..f0cc941
--- /dev/null
+++ b/src/drivers/spi/acpi/chip.h
@@ -0,0 +1,32 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2017 Google Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef __SPI_ACPI_CHIP_H__
+#define __SPI_ACPI_CHIP_H__
+
+#include <arch/acpi_device.h>
+
+struct drivers_spi_acpi_config {
+	const char *hid;		/* ACPI _HID (required) */
+	const char *cid;		/* ACPI _CID */
+	const char *name;		/* ACPI Device Name */
+	const char *desc;		/* Device Description */
+	unsigned uid;			/* ACPI _UID */
+	unsigned speed;		/* Bus speed in Hz (default 1MHz) */
+	const char *compat_string;	/* Compatible string for _HID=PRP0001 */
+	struct acpi_irq irq;		/* Interrupt */
+};
+
+#endif /* __SPI_ACPI_CHIP_H__ */