If the current rating for your phone charger is higher than that for the Hudl then charging should be as normal.
If it's lower then
(a) charging will take longer ; and
(b) there's a risk of the charger overheating and burning out (or even of it catching fire).
The output current rating for a Hudl charger is 2.1A (= 2100mA), so you need to ensure that any replacement charger you use can at least match that current. I'd be surprised if many phone chargers could do so, as most only provide around 0.5A (= 500mA)