Unmapping of the MMIO range can be done as a DRM-managed action, which
will take care of the unmapping on device teardown and error paths.
This will also ensure proper ordering with respect to other DRM-managed
actions that we'll be using to clean up non-primary GTs in upcoming
patches.

We have not yet enabled any non-root GTs in the driver yet, so the
kfree() of the GT structure is effectively dead code.  When we do start
enabling non-root GTs in upcoming patches, those are going to be using
DRM-managed allocations tied to the device lifetime, so we don't need to
explicitly free them (and kfree would be incorrect anyway).
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220906234934.3655440-5-matthew.d.roper@intel.comSigned-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>