[ddktl] Add missing dep

Adds a mising public_deps on //sdk/lib/component/incoming/cpp when
building for Fuchsia.

Change-Id: I556137f75dc79aca58da2d3def746cad1fef8976
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1152717
Fuchsia-Auto-Submit: Ian McKellar <[email protected]>
Reviewed-by: Suraj Malhotra <[email protected]>
Commit-Queue: Auto-Submit <[email protected]>

Author: ianloic

src/lib/ddktl/BUILD.gn

@@ -66,6 +66,9 @@ source_set("ddktl") {
 
       # <ddktl/metadata_server.h> has #include <lib/driver/outgoing/cpp/outgoing_directory.h>
       "//sdk/lib/driver/outgoing/cpp",
+
+      # <ddktl/device.h> has #include <lib/component/incoming/cpp/protocol.h>.
+      "//sdk/lib/component/incoming/cpp",
     ]
   }