ehci-hcd: Add init_after_reset

Some host controllers need addidional initialization after ehci_reset()
In non-dm implementation it is possible to use CONFIG_EHCI_HCD_INIT_AFTER_RESET.
This patch adds similar option to ehci drivers using dm.

Signed-off-by: Mateusz Kulikowski <mateusz.kulikowski@gmail.com>
Acked-by: Marek Vasut <marex@denx.de>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>