libertas: fix power save issue in libertas_sdio module

The problem: "iwconfig ethX power on" returns error

The cause: "ps_supported" flag was never set for SD8385/8686

The fix: check firmware capabilities returned by GET_HW_SPEC command.
Set "ps_supported" to 1 if FW_CAPINFO_PS bit is on. This fix applies
to SDIO interface only.

Signed-off-by: Bing Zhao <bzhao@marvell.com>
Acked-by: Dan Williams <dcbw@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/libertas/defs.h b/drivers/net/wireless/libertas/defs.h
index 6388b05..e8dfde3 100644
--- a/drivers/net/wireless/libertas/defs.h
+++ b/drivers/net/wireless/libertas/defs.h
@@ -265,6 +265,7 @@
 
 #define	CMD_F_HOSTCMD		(1 << 0)
 #define FW_CAPINFO_WPA  	(1 << 0)
+#define FW_CAPINFO_PS  		(1 << 1)
 #define FW_CAPINFO_FIRMWARE_UPGRADE	(1 << 13)
 #define FW_CAPINFO_BOOT2_UPGRADE	(1<<14)
 #define FW_CAPINFO_PERSISTENT_CONFIG	(1<<15)