Include BoardConfigKernel.mk to build kernel

BoardConfigKernel contains additional flags that help build
kernel. Including it here so that flags get set.

Change-Id: Ib994a3718ca4d89ab12d246ca30e93a44e4f4698
diff --git a/AndroidBoard.mk b/AndroidBoard.mk
index 9bf2008..30926d3 100644
--- a/AndroidBoard.mk
+++ b/AndroidBoard.mk
@@ -16,6 +16,9 @@
 TARGET_KERNEL_SOURCE := kernel/msm8974
 BOARD_KERNEL_IMAGE_NAME := zImage
 
+# Include Kernel Config file
+include device/fairphone/FP2/BoardConfigKernel.mk
+
 include kernel/msm8974/AndroidKernel.mk
 
 $(INSTALLED_KERNEL_TARGET): $(TARGET_PREBUILT_KERNEL) | $(ACP)