Rename bfd_bread and bfd_bwrite

These were renamed from bfd_read and bfd_write back in 2001 when they
lost an unnecessary parameter.  Rename them back, and get rid of a few
casts that are only needed without prototyped functions (K&R C).

sim/rx/load.c

@@ -153,7 +153,7 @@ rx_load (bfd *prog, host_callback *callback)
 	  fprintf (stderr, "Failed to seek to offset %lx\n", (long) offset);
 	  continue;
 	}
-      if (bfd_bread (buf, size, prog) != size)
+      if (bfd_read (buf, size, prog) != size)
 	{
 	  fprintf (stderr, "Failed to read %" PRIx64 " bytes\n",
 		   (uint64_t) size);