usb: dwc3: core: add helper to extract trb type

This helper will be used later to convert trb type
into a human-readable string for debugfs.
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc3/core.h

@@ -580,6 +580,7 @@ enum dwc3_link_state {
 #define DWC3_TRB_CTRL_IOC		(1 << 11)
 #define DWC3_TRB_CTRL_SID_SOFN(n)	(((n) & 0xffff) << 14)
 
+#define DWC3_TRBCTL_TYPE(n)		((n) & (0x3f << 4))
 #define DWC3_TRBCTL_NORMAL		DWC3_TRB_CTRL_TRBCTL(1)
 #define DWC3_TRBCTL_CONTROL_SETUP	DWC3_TRB_CTRL_TRBCTL(2)
 #define DWC3_TRBCTL_CONTROL_STATUS2	DWC3_TRB_CTRL_TRBCTL(3)