kdbus: Add magic value

kdbus: Add magic value

[partially picked from commit 216823ac83c0ab89348e2ed6f66179f53626586e]

except of all the kdbus driver, add magic value of it only.

Original authors of the files are those from commit 216823ac83c0ab8934.

Cherry-picked from 4.14 commit 970070c4f68f113284f86cf7b6fbd23d6b35b511.

Change-Id: Id60af5faf794fc4ae7122976621076f1021f6c38
Signed-off-by: Adrian Szyndela <adrian.s@samsung.com>
Signed-off-by: Hyotaek Shim <hyotaek.shim@samsung.com>
Signed-off-by: Łukasz Stelmach <l.stelmach@samsung.com>
Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>