libertas: if_spi: add ability to call board specific setup/teardown methods

In certain cases it is required to perform board specific actions
before activating libertas G-SPI interface. These actions may include
power up of the chip, GPIOs setup, proper pin-strapping and SPI
controller config.
This patch adds ability to call board specific setup/teardown methods

Signed-off-by: Mike Rapoport <mike@compulab.co.il>
Acked-by: Andrey Yurovsky <andrey@cozybit.com>
Acked-by: Dan Williams <dcbw@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/include/linux/spi/libertas_spi.h b/include/linux/spi/libertas_spi.h
index ada71b4..79506f5 100644
--- a/include/linux/spi/libertas_spi.h
+++ b/include/linux/spi/libertas_spi.h
@@ -10,6 +10,9 @@
  */
 #ifndef _LIBERTAS_SPI_H_
 #define _LIBERTAS_SPI_H_
+
+struct spi_device;
+
 struct libertas_spi_platform_data {
 	/* There are two ways to read data from the WLAN module's SPI
 	 * interface. Setting 0 or 1 here controls which one is used.
@@ -21,5 +24,9 @@
 
 	/* GPIO number to use as chip select */
 	u16 gpio_cs;
+
+	/* Board specific setup/teardown */
+	int (*setup)(struct spi_device *spi);
+	int (*teardown)(struct spi_device *spi);
 };
 #endif