hwc: Call blank ioctls

The blank ioctls were never called, we were relying on
the driver to implicitly do this on suspend/resume.
Fix this by calling blank with the right parameters.

Change-Id: Ib969c4e55d9f460255750f07aecefb04a310bd7a
diff --git a/libhwcomposer/hwc.cpp b/libhwcomposer/hwc.cpp
index ab5b144..05bb61d 100644
--- a/libhwcomposer/hwc.cpp
+++ b/libhwcomposer/hwc.cpp
@@ -139,10 +139,15 @@
 static int hwc_blank(struct hwc_composer_device_1* dev, int dpy, int blank)
 {
     //XXX: Handle based on dpy
+    hwc_context_t* ctx = (hwc_context_t*)(dev);
+    private_module_t* m = reinterpret_cast<private_module_t*>(
+        ctx->mFbDev->common.module);
     if(blank) {
-        hwc_context_t* ctx = (hwc_context_t*)(dev);
         ctx->mOverlay->setState(ovutils::OV_CLOSED);
         ctx->qbuf->unlockAllPrevious();
+        ioctl(m->framebuffer->fd, FBIOBLANK, FB_BLANK_POWERDOWN);
+    } else {
+        ioctl(m->framebuffer->fd, FBIOBLANK, FB_BLANK_UNBLANK);
     }
     return 0;
 }