USB: gadget: Add 10 microsec delay before fetching setup_data

USB hardware sometimes generate interrupt before 8 bytes of
SETUP packet are written to system memory.
This results in wrong setup_data when tried to read immediately
after receiving an interrupt.
Add a delay of 10 microsec before fetching setup packet to allow
writes from hardware to system memory to complete.

CRs-Fixed: 291466
Change-Id: Ibd14b0705eae05f13aa4166436f29252ea63e0df
Signed-off-by: Vijayavardhan Vennapusa <vvreddy@codeaurora.org>
Signed-off-by: Manu Gautam <mgautam@codeaurora.org>