drm/i915/gvt: replace idr_init() by idr_init_base()

idr_init() uses base 0 which is an invalid identifier. The new function
idr_init_base allows IDR to set the ID lookup from base 1. This avoids
all lookups that otherwise starts from 0 since 0 is always unused.

References: commit 6ce711f2 ("idr: Make 1-based IDRs more efficient")
Reviewed-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Deepak R Varma <mh12gx2825@gmail.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20201104121532.GA48202@localhost

drivers/gpu/drm/i915/gvt/gvt.c

@@ -312,7 +312,7 @@ int intel_gvt_init_device(struct drm_i915_private *i915)
 
 	gvt_dbg_core("init gvt device\n");
 
-	idr_init(&gvt->vgpu_idr);
+	idr_init_base(&gvt->vgpu_idr, 1);
 	spin_lock_init(&gvt->scheduler.mmio_context_lock);
 	mutex_init(&gvt->lock);
 	mutex_init(&gvt->sched_lock);

drivers/gpu/drm/i915/gvt/vgpu.c

@@ -392,7 +392,7 @@ static struct intel_vgpu *__intel_gvt_create_vgpu(struct intel_gvt *gvt,
 	mutex_init(&vgpu->dmabuf_lock);
 	INIT_LIST_HEAD(&vgpu->dmabuf_obj_list_head);
 	INIT_RADIX_TREE(&vgpu->page_track_tree, GFP_KERNEL);
-	idr_init(&vgpu->object_idr);
+	idr_init_base(&vgpu->object_idr, 1);
 	intel_vgpu_init_cfg_space(vgpu, param->primary);
 	vgpu->d3_entered = false;