mi: unify MI Get Log Page function with ioctl API

mi: unify MI Get Log Page function with ioctl API

In the MI interface, we currently have:

  nvme_mi_admin_get_log_page(...)

However, the ioctl-backed API equivalent doesn't use the _page:

  nvme_get_log(...)

This change makes the MI version consistent, where we have the
equivalent names, just with the mi_<type> prefix:

   nvme_mi_admin_get_log(...)

Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>