wlan: protect the DXE low resource timer by a compilation flag

DXE low resource timer is started when DXE detects that VOSS
packets are not available for receiving packets and if the
VOSS resources are not made available within the timer
expiration deadline it will panic the system. Add the
timer code within a compilation flag so that the users
can choose to use the driver without the low resource
timer.

Change-Id: Icbb6ddfe3ab59fc52e545f3f2a5e7a18809bee1a
CRs-Fixed: 627231
diff --git a/Kbuild b/Kbuild
index c0bb1ab..72129ce 100644
--- a/Kbuild
+++ b/Kbuild
@@ -546,7 +546,8 @@
                 -DFEATURE_WLAN_PAL_TIMER_DISABLE \
                 -DFEATURE_WLAN_PAL_MEM_DISABLE \
                 -DFEATURE_WLAN_CH144 \
-                -DWLAN_BUG_ON_SKB_ERROR
+                -DWLAN_BUG_ON_SKB_ERROR \
+                -DWLAN_DXE_LOW_RESOURCE_TIMER
 
 ifneq ($(CONFIG_PRONTO_WLAN),)
 CDEFINES += -DWCN_PRONTO