linux_spu_make_corefile_notes: return note_data instead of nullptr

Since commit

  9018be2 ("Make target_read_alloc & al return vectors")

the test gdb.threads/gcore-stale-thread.exp test results in UNSUPPORTED:

  UNSUPPORTED: gdb.threads/gcore-stale-thread.exp: save a corefile

The problem is that the linux_spu_make_corefile_notes started returning
nullptr when reading TARGET_OBJECT_SPU fails.  The previous (and proper)
behaviour is to return the note_data received as a parameter, so that
other functions may continue to append to this buffer.

With this patch, the test goes back to PASS.

gdb/ChangeLog:

	* linux-tdep.c (linux_spu_make_corefile_notes): Return note_data
	instead of nullptr.

1 files changed, 1 insertions, 1 deletions

diff --git a/gdb/linux-tdep.c b/gdb/linux-tdep.c
index 552a2a4..24bfd74 100644
--- a/gdb/linux-tdep.c
+++ b/gdb/linux-tdep.c
@@ -1426,7 +1426,7 @@ linux_spu_make_corefile_notes (bfd *obfd, char *note_data, int *note_size)
     spu_ids = target_read_alloc (&current_target, TARGET_OBJECT_SPU, NULL);
 
   if (!spu_ids)
-    return nullptr;
+    return note_data;
 
   /* Generate corefile notes for each SPU file.  */
   for (size_t i = 0; i < spu_ids->size (); i += 4)