fix building issues of 64-bit targets

Just change the 'data' field of gralloc_drm_handle_t
to be a pointer to struct gralloc_drm_bo_t.

Fix some warnings as well.
diff --git a/gralloc_drm.c b/gralloc_drm.c
index bd38d57..31ac988 100644
--- a/gralloc_drm.c
+++ b/gralloc_drm.c
@@ -211,10 +211,10 @@
 		}
 
 		handle->data_owner = gralloc_drm_get_pid();
-		handle->data = (int) bo;
+		handle->data = bo;
 	}
 
-	return (struct gralloc_drm_bo_t *) handle->data;
+	return handle->data;
 }
 
 /*
@@ -296,7 +296,7 @@
 	bo->refcount = 1;
 
 	handle->data_owner = gralloc_drm_get_pid();
-	handle->data = (int) bo;
+	handle->data = bo;
 
 	return bo;
 }
@@ -365,7 +365,7 @@
 	uint32_t *pitches, uint32_t *offsets, uint32_t *handles)
 {
 	struct gralloc_drm_handle_t *handle = gralloc_drm_handle(_handle);
-	struct gralloc_drm_bo_t *bo = (struct gralloc_drm_bo_t *) handle->data;
+	struct gralloc_drm_bo_t *bo = handle->data;
 	struct gralloc_drm_t *drm = bo->drm;
 
 	/* if handle exists and driver implements resolve_format */
diff --git a/gralloc_drm_handle.h b/gralloc_drm_handle.h
index f7b03b2..7fc4746 100644
--- a/gralloc_drm_handle.h
+++ b/gralloc_drm_handle.h
@@ -31,6 +31,8 @@
 extern "C" {
 #endif
 
+struct gralloc_drm_bo_t;
+
 struct gralloc_drm_handle_t {
 	native_handle_t base;
 
@@ -50,7 +52,7 @@
 	int stride; /* the stride in bytes */
 
 	int data_owner; /* owner of data (for validation) */
-	int data;       /* pointer to struct gralloc_drm_bo_t */
+	struct gralloc_drm_bo_t *data; /* pointer to struct gralloc_drm_bo_t */
 };
 
 static inline struct gralloc_drm_handle_t *gralloc_drm_handle(buffer_handle_t _handle)
diff --git a/gralloc_drm_kms.c b/gralloc_drm_kms.c
index 0909361..cb02a13 100644
--- a/gralloc_drm_kms.c
+++ b/gralloc_drm_kms.c
@@ -299,7 +299,7 @@
 	uint32_t src_w,
 	uint32_t src_h)
 {
-	unsigned int i, j;
+	int j;
 	struct gralloc_drm_handle_t *drm_handle =
 		gralloc_drm_handle(handle);
 	int plane_count = drm->plane_resources->count_planes;
@@ -1092,15 +1092,14 @@
 	if (!drm->plane_resources) {
 		ALOGD("no planes found from drm resources");
 	} else {
+		unsigned int i, j;
+
 		ALOGD("supported drm planes and formats");
 		/* fill a helper structure for hwcomposer */
 		drm->planes = calloc(drm->plane_resources->count_planes,
 			sizeof(struct gralloc_drm_plane_t));
 
 		for (i = 0; i < drm->plane_resources->count_planes; i++) {
-
-			unsigned int j;
-
 			drm->planes[i].drm_plane = drmModeGetPlane(drm->fd,
 				drm->plane_resources->planes[i]);