i2c: Export i2c_deblock_gpio_loop()

Export the i2c_deblock_gpio_loop() so it can be used in other places in
U-Boot. In particular, this is useful in the GPIO I2C driver, which claims
the SDA/SCL GPIOs and thus prevents the i2c_deblock() implementation from
claiming the pins as GPIOs again.

Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Heiko Schocher <hs@denx.de>
diff --git a/include/i2c.h b/include/i2c.h
index 0faf854..7c92042 100644
--- a/include/i2c.h
+++ b/include/i2c.h
@@ -331,6 +331,22 @@
 int i2c_deblock(struct udevice *bus);
 
 /**
+ * i2c_deblock_gpio_loop() - recover a bus from an unknown state by toggling SDA/SCL
+ *
+ * This is the inner logic used for toggling I2C SDA/SCL lines as GPIOs
+ * for deblocking the I2C bus.
+ *
+ * @sda_pin:	SDA GPIO
+ * @scl_pin:	SCL GPIO
+ * @scl_count:	Number of SCL clock cycles generated to deblock SDA
+ * @delay:	Delay between SCL clock line changes
+ * @return 0 if OK, -ve on error
+ */
+struct gpio_desc;
+int i2c_deblock_gpio_loop(struct gpio_desc *sda_pin, struct gpio_desc *scl_pin,
+			  unsigned int scl_count, unsigned int delay);
+
+/**
  * struct dm_i2c_ops - driver operations for I2C uclass
  *
  * Drivers should support these operations unless otherwise noted. These