usb: mtu3: mtu3_debug: remove an unused struct member

The "nregs" member is not used.  The code uses the "regset.nregs"
struct member instead.

Acked-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/X8ikv1QA3Do50D+R@mwanda
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/mtu3/mtu3_debug.h

@@ -19,7 +19,6 @@ struct ssusb_mtk;
 struct mtu3_regset {
 	char name[MTU3_DEBUGFS_NAME_LEN];
 	struct debugfs_regset32 regset;
-	size_t nregs;
 };
 
 struct mtu3_file_map {