usbh: add enumeration control transfer timeout

A device that ACKs SETUP but never completes the following stage (e.g. NAKs
the EP0 IN data stage forever) froze the control state machine: enumeration
never finishes and hub interrupt polling never resumes, so one dead device
blocks all further enumeration on the bus. Observed with a degraded USB disk
behind a hub on a rp2040 PIO-USB host: wire capture shows SETUP ACKed then
an endless IN/NAK storm with no completion event.

Arm a watchdog (CFG_TUH_ENUM_TIMEOUT_MS, default 5s to match Linux's
USB_CTRL_GET_TIMEOUT, 0 disables) on enumeration-owned control transfers
using the existing call_after slot, which already wakes a blocked host task.
On expiry abort the transfer at hcd level and complete it as FAILED so the
normal enumeration failure path frees dev0 and resumes hub polling.
Non-enumeration control transfers keep their current behavior.