usb: gadget: remove unnecessary AND operation when get ep maxp

usb_endpoint_maxp() already returns actual max packet size, no need
to AND 0x7ff.

Acked-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/1628836253-7432-7-git-send-email-chunfeng.yun@mediatek.com


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