pleorasrc: fix handling of strides that aren't 32-bit aligned

For example, a Mono8 642x482 would have failed to work, as GStreamer
expects the stride to be a multiple of 4-bytes, that is 644 bytes in
this example, while Pleora doesn't do this alignment. This incurs a copy
unfortunately, and there might be a way with memory meta to avoid this,
however eventually most elements will need to have the data 4-byte
aligned.

sys/pleora/gstpleorasrc.h

@@ -62,7 +62,7 @@ struct _GstPleoraSrc
   GstCaps *caps;
   gint height;
   gint gst_stride;
-  gint bf_stride;
+  gint pleora_stride;
 
   gboolean stop_requested;
 };