wlan: Create wlan/prima directory in firmware path if not exists.

Create wlan/prima folder in etc/firmware path if it doesn't exist
before making attempt to copy WCNSS_cfg.dat file from
prima/firmware_bin folder.

Change-Id: I8c978fa3a687a8041f835512f3714120f9d4da13
CRs-Fixed: 687986
diff --git a/Android.mk b/Android.mk
index 4bfb763..fee5a01 100644
--- a/Android.mk
+++ b/Android.mk
@@ -46,6 +46,7 @@
 # Copy WCNSS_cfg.dat file from firmware_bin/ folder to target out directory.
 ifeq ($(WLAN_PROPRIETARY),0)
 
+$(shell mkdir -p $(TARGET_OUT_ETC)/firmware/wlan/prima)
 $(shell rm -f $(TARGET_OUT_ETC)/firmware/wlan/prima/WCNSS_cfg.dat)
 $(shell cp $(LOCAL_PATH)/firmware_bin/WCNSS_cfg.dat $(TARGET_OUT_ETC)/firmware/wlan/prima)