usb: gadget: avoid unusual inline assembly

clang does not understand the "mrc%?" syntax:

drivers/usb/gadget/udc/pxa25x_udc.c:2330:11: error: invalid % escape in inline assembly string

I don't understand it either, but removing the %? here gets it to build.
This is probably wrong and someone else should do a proper patch.

Any suggestions?

Signed-off-by: Arnd Bergmann <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/gadget/udc/pxa25x_udc.c

···
 	pr_info("%s: version %s\n", driver_name, DRIVER_VERSION);
 
 	/* insist on Intel/ARM/XScale */
-	asm("mrc%? p15, 0, %0, c0, c0" : "=r" (chiprev));
+	asm("mrc p15, 0, %0, c0, c0" : "=r" (chiprev));
 	if ((chiprev & CP15R0_VENDOR_MASK) != CP15R0_XSCALE_VALUE) {
 		pr_err("%s: not XScale!\n", driver_name);
 		return -ENODEV;