usb: mtu3: print endpoint type as string

Print endpoint type as string instead of decimal value to make
the log more readable.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/20220708071903.25752-2-chunfeng.yun@mediatek.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>