kpb: add missing initialization of new memory block

This patch initializes early the "next" pointer of
new memory block. This is important because if
further allocation fails (i.e due to not enough
memory available) this block will end up with missing
next pointer so every operatation on linked list of buffers
will likely fail (assuming there is no check for NULL pointer)

Signed-off-by: Marcin Rajwa <marcin.rajwa@linux.intel.com>

src/audio/kpb.c

@@ -264,6 +264,7 @@ static size_t kpb_allocate_history_buffer(struct comp_data *kpb,
 				if (!new_hb)
 					return 0;
 				history_buffer->next = new_hb;
+				new_hb->next = kpb->history_buffer;
 				new_hb->state = KPB_BUFFER_OFF;
 				new_hb->prev = history_buffer;
 				history_buffer = new_hb;