drivers/i2c/designware/dw_i2c: limit scope of dw_i2c_transfer

Outside of the designware I2C driver the generic platform_i2c_transfer
function should be used instead, so don't make dw_i2c_transfer available
outside of this file.

Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: Ib8b6a08b6aa2cd63adc2ef69b828661fa0ed154a
Reviewed-on: https://review.coreboot.org/c/coreboot/+/61514
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Raul Rangel <rrangel@chromium.org>
diff --git a/src/drivers/i2c/designware/dw_i2c.c b/src/drivers/i2c/designware/dw_i2c.c
index 011b38b..bfb5971 100644
--- a/src/drivers/i2c/designware/dw_i2c.c
+++ b/src/drivers/i2c/designware/dw_i2c.c
@@ -453,7 +453,7 @@
 	return ret;
 }
 
-enum cb_err dw_i2c_transfer(unsigned int bus, const struct i2c_msg *msg, size_t count)
+static enum cb_err dw_i2c_transfer(unsigned int bus, const struct i2c_msg *msg, size_t count)
 {
 	const struct i2c_msg *orig_msg = msg;
 	size_t i;
diff --git a/src/drivers/i2c/designware/dw_i2c.h b/src/drivers/i2c/designware/dw_i2c.h
index 847b6c3..3d8e663 100644
--- a/src/drivers/i2c/designware/dw_i2c.h
+++ b/src/drivers/i2c/designware/dw_i2c.h
@@ -110,13 +110,6 @@
 					struct dw_i2c_speed_config *config);
 
 /*
- * Process given I2C segments in a single transfer
- */
-enum cb_err dw_i2c_transfer(unsigned int bus,
-			const struct i2c_msg *segments,
-			size_t count);
-
-/*
  * Map an i2c host controller device to a logical bus number.
  * Return value:
  * -1 = failure