accel/ivpu: Remove skip of dma unmap for imported buffers

accel/ivpu: Remove skip of dma unmap for imported buffers

Rework of imported buffers introduced in the commit
e0c0891cd63b ("accel/ivpu: Rework bind/unbind of imported buffers")
switched the logic of imported buffers by dma mapping/unmapping
them just as the regular buffers.

The commit didn't include removal of skipping dma unmap of imported
buffers which results in them being mapped without unmapping.

Fixes: e0c0891cd63b ("accel/ivpu: Rework bind/unbind of imported buffers")
Reviewed-by: Jeff Hugo <jeff.hugo@oss.qualcomm.com>
Reviewed-by: Karol Wachowski <karol.wachowski@linux.intel.com>
Signed-off-by: Maciej Falkowski <maciej.falkowski@linux.intel.com>
Link: https://patch.msgid.link/20251027150933.2384538-1-maciej.falkowski@linux.intel.com