dsp: pdr: Replace ENOKEY with ENOENT

Make pldm_pdr_find_child_container_id_index_range_exclude() return
ENOENT, since that is a standard errno. ENOKEY is Linux specific.

pldm_pdr_find_child_container_id_index_range_exclude() is marked as
TESTING ABI, so the change in error code should be OK.

Change-Id: I3fb3076b236e4e3b1c31f13d819dcaca38076a5d
Signed-off-by: Matt Johnston <matt@codeconstruct.com.au>
diff --git a/src/dsp/pdr.c b/src/dsp/pdr.c
index ccaa929..0ef1686 100644
--- a/src/dsp/pdr.c
+++ b/src/dsp/pdr.c
@@ -445,7 +445,7 @@
 			return 0;
 		}
 	}
-	return -ENOKEY;
+	return -ENOENT;
 }
 
 typedef struct pldm_entity_association_tree {