libertas: if_spi, driver for libertas GSPI devices

Add initial support for libertas devices using a GSPI interface.  This has
been tested with the 8686.

GSPI is intended to be used on embedded systems. Board-specific parameters are
required (see libertas_spi.h).

Thanks to everyone who took a look at the earlier versions of the patch.

Signed-off-by: Colin McCabe <colin@cozybit.com>
Signed-off-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/drivers/net/wireless/Kconfig b/drivers/net/wireless/Kconfig
index e4f9f74..2dddbd0 100644
--- a/drivers/net/wireless/Kconfig
+++ b/drivers/net/wireless/Kconfig
@@ -151,6 +151,12 @@
 	---help---
 	  A driver for Marvell Libertas 8385 and 8686 SDIO devices.
 
+config LIBERTAS_SPI
+	tristate "Marvell Libertas 8686 SPI 802.11b/g cards"
+	depends on LIBERTAS && SPI && GENERIC_GPIO
+	---help---
+	  A driver for Marvell Libertas 8686 SPI devices.
+
 config LIBERTAS_DEBUG
 	bool "Enable full debugging output in the Libertas module."
 	depends on LIBERTAS