drm/xe: Reject BO eviction if BO is bound to current VM

drm/xe: Reject BO eviction if BO is bound to current VM

This is a follow up fix for
https://patchwork.freedesktop.org/patch/msgid/20241203021929.1919730-1-oak.zeng@intel.com
The overall goal is to fail vm_bind when there is memory pressure. See more
details in the commit message of above patch. Abbove patch fixes the issue
when user pass in a vm_id parameter during gem_create. If user doesn't pass
in a vm_id during gem_create, above patch doesn't help.

This patch further reject BO eviction (which could be triggered by bo validation)
if BO is bound to the current VM. vm_bind could fail due to the eviction failure.
The BO to VM reverse mapping structure is used to determine whether BO is bound
to VM.

v2:
Move vm_bo definition from function scope to if(evict) clause (Thomas)
Further constraint the condition by adding ctx->resv (Thomas)
Add a short comment describe the change.

Suggested-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Oak Zeng <oak.zeng@intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250110210137.3181576-1-oak.zeng@intel.com