wl1251: add power callback to wl1251_if_operations

Call interface specific power callback before calling board specific
one. Also allow that callback to fail. This is how it's done for
wl1271 and will be used for runtime_pm support.

Signed-off-by: Grazvydas Ignotas <notasas@gmail.com>
Acked-by: Kalle Valo <kvalo@adurom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/wl1251/spi.c b/drivers/net/wireless/wl1251/spi.c
index 88fa8e6..ac872b3 100644
--- a/drivers/net/wireless/wl1251/spi.c
+++ b/drivers/net/wireless/wl1251/spi.c
@@ -215,12 +215,21 @@
 	return disable_irq(wl->irq);
 }
 
+static int wl1251_spi_set_power(struct wl1251 *wl, bool enable)
+{
+	if (wl->set_power)
+		wl->set_power(enable);
+
+	return 0;
+}
+
 static const struct wl1251_if_operations wl1251_spi_ops = {
 	.read = wl1251_spi_read,
 	.write = wl1251_spi_write,
 	.reset = wl1251_spi_reset_wake,
 	.enable_irq = wl1251_spi_enable_irq,
 	.disable_irq = wl1251_spi_disable_irq,
+	.power = wl1251_spi_set_power,
 };
 
 static int __devinit wl1251_spi_probe(struct spi_device *spi)