switch default hwc from TI to DRM

Default TI hwcomposer is replaced with DRM hwcomposer.
Reason - TI hwc is not working properly (the home screen
is not loading).

Features missing for DRM HWC at the moment:
 - dual display support;
 - HDMI hotplug.

These features are expected in nearest future.

To turn on TI hwcomposer instead of DRM one - set
flag USE_TI_HWC=y during the build.

Change-Id: I949cdc53266a83f46255b314b5b6582792ad5ebd
Signed-off-by: Mykhailo Sopiha <mykhailo.sopiha@linaro.org>
diff --git a/device.mk b/device.mk
index 60dd4cd..081e0b9 100644
--- a/device.mk
+++ b/device.mk
@@ -82,12 +82,11 @@
 	memtrack.am57x \
 	pvrsrvctl \
 
-ifeq ($(USE_DRM_HWC), y)
-PRODUCT_PACKAGES += hwcomposer.drm_imagination
-PRODUCT_PROPERTY_OVERRIDES += \
-	ro.hardware.hwcomposer=drm_imagination \
-else
+ifeq ($(USE_TI_HWC), y)
 PRODUCT_PACKAGES += hwcomposer.am57x
+else
+PRODUCT_PACKAGES += hwcomposer.drm_imagination
+PRODUCT_PROPERTY_OVERRIDES += ro.hardware.hwcomposer=drm_imagination
 endif
 
 #Health