cell: call cell_flush_int() at end of cell_create_context()

Ensures that SPUs are initialized/ready before proceeding.
This fixes a spurious assertion failure when the SPU-side shader function info
hasn't been returned to the PPU before shader codegen.

src/gallium/drivers/cell/ppu/cell_context.c

@@ -162,5 +162,8 @@ cell_create_context(struct pipe_screen *screen,
 
    cell_init_batch_buffers(cell);
 
+   /* make sure SPU initializations are done before proceeding */
+   cell_flush_int(cell, CELL_FLUSH_WAIT);
+
    return &cell->pipe;
 }