OpenWrt/Atheros: Fix detecting Atheros driver type for openwrt

When Radio is of type Offload, /sys/module/ath_hal entry is not
available due to recent division of HOST changes for Direct-Attach and
Offload code. So to check for openwrt_driver_type, verify umac driver
name, entry in "/sys/module/umac" than "/sys/module/ath_hal". That entry
is available for both cases.

Signed-off-by: Sarvepalli, Rajesh Babu <c_rsarve@qti.qualcomm.com>
diff --git a/utils.c b/utils.c
index a021d76..8464d34 100644
--- a/utils.c
+++ b/utils.c
@@ -75,7 +75,7 @@
 	struct stat s;
 
 	if (openwrt_chip_type == OPENWRT_DRIVER_NOT_SET) {
-		if (stat("/sys/module/ath_hal", &s) == 0)
+		if (stat("/sys/module/umac", &s) == 0)
 			openwrt_chip_type = OPENWRT_DRIVER_ATHEROS;
 	}