softpipe: remove >32bpp color restriction

The comment was out of date.  The tile cache does handle >32-bit colors.

src/gallium/drivers/softpipe/sp_screen.c

@@ -209,13 +209,6 @@ softpipe_is_format_supported( struct pipe_screen *screen,
       if (format_desc->block.width != 1 ||
           format_desc->block.height != 1)
          return FALSE;
-
-      /*
-       * TODO: Unfortunately we cannot render into anything more than 32 bits
-       * because we encode color clear values into a 32bit word.
-       */
-      if (format_desc->block.bits > 32)
-         return FALSE;
    }
 
    if (bind & PIPE_BIND_DEPTH_STENCIL) {