drm/xe: Add warn when level can not be zero.

At xe_pt_zap_ptes_entry() and xe_pt_stage_unbind_entry, the level cannot
be 0. Therefore, add an independent check for the level. Since the level
cannot be zero at this point, there is no need to check for `is_compact`,
so remove that instead.

Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240521103623.11645-1-nirmoy.das@intel.comSigned-off-by: Nirmoy Das <nirmoy.das@intel.com>

drivers/gpu/drm/xe/xe_pt.c

@@ -763,7 +763,7 @@ static int xe_pt_zap_ptes_entry(struct xe_ptw *parent, pgoff_t offset,
 	pgoff_t end_offset;
 
 	XE_WARN_ON(!*child);
-	XE_WARN_ON(!level && xe_child->is_compact);
+	XE_WARN_ON(!level);
 
 	/*
 	 * Note that we're called from an entry callback, and we're dealing
@@ -1445,7 +1445,7 @@ static int xe_pt_stage_unbind_entry(struct xe_ptw *parent, pgoff_t offset,
 	struct xe_pt *xe_child = container_of(*child, typeof(*xe_child), base);
 
 	XE_WARN_ON(!*child);
-	XE_WARN_ON(!level && xe_child->is_compact);
+	XE_WARN_ON(!level);
 
 	xe_pt_check_kill(addr, next, level - 1, xe_child, action, walk);