Camera: Add makefile support for camera drivers

This change adds dummy Makefile support to compile camera
driver project along with base kernel.

Change-Id: I237ba87442c17869b7cc264371c5c3996f43eb95
Signed-off-by: Jigarkumar Zala <jzala@codeaurora.org>

Makefile

@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+ccflags-y := -Wno-unused-function
+obj-y := camera_stub.o