usb: dwc3: trace: Refactor nested switch to make compiler happy

The missed break statement in the outer switch makes the code fall through always and thus always same value will be printed.

Besides that, compiler warns about missed fall through marker:

drivers/usb/dwc3/./trace.h: In function ‘trace_raw_output_dwc3_log_trb’:
drivers/usb/dwc3/./trace.h:246:4: warning: this statement may fall through [-Wimplicit-fallthrough=]

    switch (pcm) {
    ^~~~~~

Refactor nested switch statements to work correctly without compilation warnings.

Fixes fa8d965d736b ("usb: dwc3: trace: pretty print high-bandwidth transfers too")

Cc Felipe Balbi <[email protected]>

Signed-off-by Andy Shevchenko <[email protected]>

---
 drivers/usb/dwc3/trace.h | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

drivers/usb/dwc3/trace.h +1 -1

index f22714cce070..8e1625a6c19f 100644
@@ -238,7 +238,7 @@ DECLARE_EVENT_CLASS(dwc3_log_trb,
 	),
 	TP_printk("%s: trb %p buf %08x%08x size %s%d ctrl %08x (%c%c%c%c:%c%c:%s)",
 		__get_str(name), __entry->trb, __entry->bph, __entry->bpl,
-		({char *s;
+		({ char *s = "";
 		int pcm = ((__entry->size >> 24) & 3) + 1;
 		switch (__entry->type) {
 		case USB_ENDPOINT_XFER_INT: