USB: ti_usb_3410_5052: removed duplicated include

Removed duplicated #include <linux/firmware.h> in
drivers/usb/serial/ti_usb_3410_5052.c.

Signed-off-by: Huang Weiyi <hwy@cn.fujitsu.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>