usb: dwc3: st: add missing <linux/pinctrl/consumer.h> include

dwc3-st uses pinctrl_pm_select_*_state() however it
doesn't include the necessary header. Fix the build
break caused by that, by simply including the
missing header.

Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
diff --git a/drivers/usb/dwc3/dwc3-st.c b/drivers/usb/dwc3/dwc3-st.c
index 89a2f71..aaaf256 100644
--- a/drivers/usb/dwc3/dwc3-st.c
+++ b/drivers/usb/dwc3/dwc3-st.c
@@ -31,6 +31,7 @@
 #include <linux/slab.h>
 #include <linux/regmap.h>
 #include <linux/reset.h>
+#include <linux/pinctrl/consumer.h>
 #include <linux/usb/of.h>
 
 #include "core.h"