Allocate ep0's USB request object when the UDC driver is probed. This
solves a couple of issues in the current code:
a) A request object always exists for ep0. Prior to this patch, if setup
transactions arrived in an unexpected order, handle_setup() would need
to reply to a setup transaction before any ep0 usb_req was created.
This issue was introduced in commit 2813006fec "usb: ci_udc: allow
multiple buffer allocs per ep."
b) handle_ep_complete no longer /has/ to queue the ep0 request again
after every single request completion. This is currently required, since
handle_setup() assumes it can find some request object in ep0's request
queue. This patch doesn't actually stop handle_ep_complete() from always
requeueing the request, but the next patch will.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
a2d8f92985