msm: camera: smmu: Enhance debug capability for camera memmgr

Improve debugging infrastructure and logging for memory related
issues. There are scenarios where the fd returned after ion_alloc
exists in camera smmu table as being mapped [stale entry].
On such scenarios, this change will return a specific error code to
userspace. The change also propagates the mapped size back to
user space.

CRs-Fixed: 2663114
Change-Id: Ia797b65d1e8ded58dec5b01df07d73262c4cfa95
Signed-off-by: Karthik Anantha Ram <kartanan@codeaurora.org>

drivers/cam_req_mgr/cam_mem_mgr.h

@@ -42,6 +42,7 @@ enum cam_smmu_mapping_client {
  * @active:      state of the buffer
  * @is_imported: Flag indicating if buffer is imported from an FD in user space
  * @is_internal: Flag indicating kernel allocated buffer
+ * @timestamp:   Timestamp at which this entry in tbl was made
  */
 struct cam_mem_buf_queue {
 	struct dma_buf *dma_buf;
@@ -58,6 +59,7 @@ struct cam_mem_buf_queue {
 	bool active;
 	bool is_imported;
 	bool is_internal;
+	struct timespec64 timestamp;
 };
 
 /**