remoteproc: Add missing kernel-doc comment for auto-boot

The commit ddf711872c9d ("remoteproc: Introduce auto-boot flag")
introduced the auto-boot flag but missed adding the corresponding
kernel-doc comment. Add the same.

Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

include/linux/remoteproc.h

@@ -439,6 +439,7 @@ struct rproc_dump_segment {
  * @cached_table: copy of the resource table
  * @table_sz: size of @cached_table
  * @has_iommu: flag to indicate if remote processor is behind an MMU
+ * @auto_boot: flag to indicate if remote processor should be auto-started
  * @dump_segments: list of segments in the firmware
  */
 struct rproc {