BAR2 being done for practical reasons, this is just for consistency.

Flushes have been added after the write to bind the instance block,
as later commits will reveal the need for them.
Signed-off-by: NBen Skeggs <bskeggs@redhat.com>

NVIDIA call it BAR2, Linux APIs treat it as BAR3 due to BAR1 being a
64-bit BAR, which I presume take two slots or something.

No actual code changes here, just to make future commits less messy.
Signed-off-by: NBen Skeggs <bskeggs@redhat.com>

Will already be done by MMU as a result of the PT writes that occur
during BAR2 bootstrapping.

This is likely just a left-over from the days when it was hardcoded.
Signed-off-by: NBen Skeggs <bskeggs@redhat.com>

Useful for testing, and for the userspace build where we can't kick
a framebuffer driver off the device.
Signed-off-by: NBen Skeggs <bskeggs@redhat.com>

Signed-off-by: NBen Skeggs <bskeggs@redhat.com>