ndis: Work around lack of C99 designated initializers in MSVC

ndis: Work around lack of C99 designated initializers in MSVC

Use a driver_ndis.c specific initialization function to fill in the
wpa_driver_ops information to make it easier to modify struct
wpa_driver_ops in the future. Being able to build driver_ndis.c
with MSVC was the only reason for having to maintain the same order
of function pointers in struct wpa_driver_ops and for having to
update driver_ndis.c for all changes in that structure.

Signed-hostap: Jouni Malinen <j@w1.fi>