ANDROID: USB gadget: mtp: Fix hang in ioctl(MTP_RECEIVE_FILE) for WritePartialObject

user space will hang at ioctl when copy file.
ioctl(mFD, MTP_RECEIVE_FILE, (unsigned long)&mfr);
length of read_req need rounded up to max packet size for usb_ep_queue,
Otherwise the read request will never complete.

Change-Id: Id8c6d7c44d1c16bb81dd77d3acc96ef2ab31f4c2
Signed-off-by: Mike Lockwood <lockwood@google.com>
Signed-off-by: zhang sanshan <sanshan.zhang@nxp.com>