drm_hwcomposer: move header files into source directory

... to improve navigation between source/header file.
Unnecessary dependencies also removed.

Signed-off-by: Roman Stratiienko <r.stratiienko@gmail.com>
Change-Id: I2c3bf993b8c5f356490433fd94e90011487a1276
diff --git a/platform/platformimagination.cpp b/platform/platformimagination.cpp
index bd4a4c3..83cebf3 100644
--- a/platform/platformimagination.cpp
+++ b/platform/platformimagination.cpp
@@ -1,6 +1,7 @@
 #define LOG_TAG "hwc-platform-imagination"
 
 #include "platformimagination.h"
+
 #include <log/log.h>
 #include <xf86drm.h>