drm/nouveau/disp/dp: fixup cr/eq delays for 1.4

Also use usleep_range() instead of [um]delay() to be a bit nicer.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Karol Herbst <kherbst@redhat.com>
Link: https://gitlab.freedesktop.org/drm/nouveau/-/merge_requests/17