qcacld-3.0: Fix Argument list too long compile issue

Change absolute path to relative to fix below compile
issue for yocto system:
make[4]: /bin/sh: Argument list too long

And just need to do like this in the bb recipes files:
1. set LINUX_BUILD_TOP="${WORKDIR}/WLANSRC"
2. keep WLAN_ROOT=""

Change-Id: I2f03eb9aa5501eae887b41b4e6a134b55da16462
CRs-Fixed: 3408645

Kbuild

@@ -31,6 +31,13 @@ ifneq ($(ANDROID_BUILD_TOP),)
       override WLAN_ROOT := $(ANDROID_BUILD_TOP_REL)/$(WLAN_ROOT)
       override WLAN_COMMON_INC := $(ANDROID_BUILD_TOP_REL)/$(WLAN_COMMON_INC)
       override WLAN_FW_API := $(ANDROID_BUILD_TOP_REL)/$(WLAN_FW_API)
+else ifneq ($(LINUX_BUILD_TOP),)
+      LINUX_BUILD_TOP_REL := $(shell python -c "import os.path; print(os.path.relpath('$(LINUX_BUILD_TOP)'))")
+      $(warning "LINUX_BUILD_TOP_REL=: $(LINUX_BUILD_TOP_REL)")
+      override WLAN_ROOT := $(LINUX_BUILD_TOP_REL)/qcacld-3.0
+      override WLAN_COMMON_ROOT ?= cmn
+      override WLAN_COMMON_INC ?= $(WLAN_ROOT)/$(WLAN_COMMON_ROOT)
+      override WLAN_FW_API := $(WLAN_ROOT)/../fw-api
 endif
 endif