drm/i915: Fix dynamic allocation of physical handles

A single object may be referenced by multiple registers fundamentally
breaking the static allotment of ids in the current design. When the
object is used the second time, the physical address of the first
assignment is relinquished and a second one granted. However, the
hardware is still reading (and possibly writing) to the old physical
address now returned to the system. Eventually hilarity will ensue, but
in the short term, it just means that cursors are broken when using more
than one pipe.

v2: Fix up leak of pci handle when handling an error during attachment,
and avoid a double kmap/kunmap. (Ville)
Rebase against -fixes.

v3: And fix the error handling added in v2 (Ville)

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=77351


Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: stable@vger.kernel.org
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>