USB: gadget: f_massstorage: Fix max packet size for Rx endpoint

commit "31ac35219203686655b8936ee9cffbe9d407e85f" is made to add
superspeed support by pulling open source patches for superspeed.
This change introduced bug in massstorage driver where TX endpoint
Wmaxpacket size is assigned instead of RX endpoint Wmaxpacket size
as RX endpoint maximum packet size. This is leading to queueing
unligned requests on Rx endpoint on platforms where DWC3 driver is
used. Hence fix the issue by assigning Rx endpoint Wmax packet size
as RX endpoint maximum packet size.

CRs-Fixed: 479410
Change-Id: I24e99add62f3e27bb9f5daaf20ccdcd773c6a9cd
Signed-off-by: Vijayavardhan Vennapusa <vvreddy@codeaurora.org>