pdr: pldm_pdr_fru_record_set_find_by_rsi(): Document reality of return

The function prototype doesn't return uint32_t, the documentation is
outright inaccurate. Update it to record that it returns a pointer that
may be NULL.

Fixes: 9c76679224cf ("libpldm: Migrate to subproject")
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Change-Id: I617e95638e708ad591dfcf5a9e1c644cd2ad01b4
diff --git a/CHANGELOG.md b/CHANGELOG.md
index d014b42..e0c7d0a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -89,6 +89,7 @@
 2. pdr: Rework pldm_pdr_find_container_id_range_exclude() API
 3. transport: mctp-demux: Don't test socket for non-zero value
 4. requester: Return PLDM_REQUESTER_OPEN_FAIL from pldm_open() on error
+5. pdr: pldm_pdr_fru_record_set_find_by_rsi(): Document reality of return
 
 ## [0.3.0] - 2023-06-23
 
diff --git a/include/libpldm/pdr.h b/include/libpldm/pdr.h
index 65aff2c..e2a1968 100644
--- a/include/libpldm/pdr.h
+++ b/include/libpldm/pdr.h
@@ -250,7 +250,7 @@
  *  @param[in] container_id - *cintainer_id will be FRU container id of found
  *  PDR, or 0 if not found
  *
- *  @return uint32_t - record handle assigned to PDR record
+ *  @return An opaque pointer to the PDR record on success, or NULL on failure
  */
 const pldm_pdr_record *pldm_pdr_fru_record_set_find_by_rsi(
 	const pldm_pdr *repo, uint16_t fru_rsi, uint16_t *terminus_handle,