acpigen: Add stop gpio control to power resource

There is at least one I2C device (being used by Soraka) that has 3
controls -- enable, reset and stop. If the stop gpio is not put into
the right state when turning off the device in suspend mode, then it
causes leakage. Thus, we need control in power resource to be able to
stop the device when entering suspend state.

BUG=b:64987428
TEST=Verified on soraka that touchscreen stop is correctly configured
on suspend.

Change-Id: Iae5ec7eb3972c5c7f80956d60d0d3c321bbefb0f
Signed-off-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: https://review.coreboot.org/21249
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/drivers/spi/acpi/chip.h b/src/drivers/spi/acpi/chip.h
index 6b541005..35341d3 100644
--- a/src/drivers/spi/acpi/chip.h
+++ b/src/drivers/spi/acpi/chip.h
@@ -47,6 +47,11 @@
 	struct acpi_gpio enable_gpio;
 	/* Delay to be inserted after device is enabled. */
 	unsigned enable_delay_ms;
+
+	/* GPIO used to stop operation of device. */
+	struct acpi_gpio stop_gpio;
+	/* Delay to be inserted after disabling stop. */
+	unsigned stop_delay_ms;
 };
 
 #endif /* __SPI_ACPI_CHIP_H__ */