clang-tidy: Fix clang-diagnostic-strict-prototypes diagnostics

Produces output such as:

```
/usr/bin/clang-tidy -checks=-*, bugprone-branch-clone -export-fixes /tmp/tmpjjns4w4i/tmp2vh08b10.yaml -p=build /mnt/host/andrew/src/openbmc/libpldm/src/platform.c
/mnt/host/andrew/src/openbmc/libpldm/build/../include/libpldm/pdr.h:35:24: error: a function declaration without a prototype is deprecated in all versions of C [clang-diagnostic-strict-prototypes]
pldm_pdr *pldm_pdr_init();
                       ^
                        void
```

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Change-Id: Ib9b679682cc25b8c1b294d2be856031f77d755d9
diff --git a/src/pdr.c b/src/pdr.c
index fe28aa9..b3a5d5a 100644
--- a/src/pdr.c
+++ b/src/pdr.c
@@ -110,7 +110,7 @@
 	return record->record_handle;
 }
 
-pldm_pdr *pldm_pdr_init()
+pldm_pdr *pldm_pdr_init(void)
 {
 	pldm_pdr *repo = malloc(sizeof(pldm_pdr));
 	assert(repo != NULL);
@@ -375,7 +375,7 @@
 	return node->entity;
 }
 
-pldm_entity_association_tree *pldm_entity_association_tree_init()
+pldm_entity_association_tree *pldm_entity_association_tree_init(void)
 {
 	pldm_entity_association_tree *tree =
 	    malloc(sizeof(pldm_entity_association_tree));