wlcore: spi: use platform_device_unregister in wl1271_remove()

platform_device_unregister() only calls platform_device_del() and
platform_device_put(), thus use platform_device_unregister() to
simplify the code.

Also the documents in platform.c shows that platform_device_del
and platform_device_put must _only_ be externally called in error
cases.  All other usage is a bug.

dpatch engine is used to auto generate this patch.
(https://github.com/weiyj/dpatch)

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Luciano Coelho <luca@coelho.fi>

drivers/net/wireless/ti/wlcore/spi.c

@@ -407,8 +407,7 @@ static int __devexit wl1271_remove(struct spi_device *spi)
 {
 	struct wl12xx_spi_glue *glue = spi_get_drvdata(spi);
 
-	platform_device_del(glue->core);
-	platform_device_put(glue->core);
+	platform_device_unregister(glue->core);
 	kfree(glue);
 
 	return 0;