Disp: add makefile support for display drivers

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

Change-Id: I4fe15e2b358227911d3826e914ccb5eb45bb3d0d
Signed-off-by: Narendra Muppalla <NarendraM@codeaurora.org>

Makefile

@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0-only
+ccflags-y := -Wno-unused-function
+obj-y := disp.o

disp.c

@@ -0,0 +1,5 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+static void _disp_techpack_stub(void)
+{
+}