gralloc: Deprecate old stuff.

1. Reclaim some old gralloc flags.
2. System heap allocation happens by default.
3. Remove some unused private flags.
4. Add heapid member to alloc_data to better line up with ion
   header
5. Remove check for MDSS_TARGET

Change-Id: I37be0a2fcd5fd4a14bb9ca235fcae41f6f3ec19e
diff --git a/libgralloc/mapper.cpp b/libgralloc/mapper.cpp
index 5382300..8b38952 100644
--- a/libgralloc/mapper.cpp
+++ b/libgralloc/mapper.cpp
@@ -204,10 +204,7 @@
 
     if (hnd->base != 0) {
         // this buffer was mapped, unmap it now
-        if (hnd->flags & (private_handle_t::PRIV_FLAGS_USES_PMEM |
-                          private_handle_t::PRIV_FLAGS_USES_PMEM_ADSP |
-                          private_handle_t::PRIV_FLAGS_USES_ASHMEM |
-                          private_handle_t::PRIV_FLAGS_USES_ION)) {
+        if (hnd->flags & private_handle_t::PRIV_FLAGS_USES_ION) {
                 gralloc_unmap(module, hnd);
         } else {
             ALOGE("terminateBuffer: unmapping a non pmem/ashmem buffer flags = 0x%x",