Ability to explicitely set if heap_id_mask or heap_mask should be used.

[z3ntu]

Apply with MR_QCOM_OVERLAY_HEAP_ID_MASK := 1 or 2 in your BoardConfig.mk. If not set, it will fall back to the old method (>= API 21)

This would fix #101

This is probably the worst C preprocessor cluster, but it seems to work. If you know how it would be better, please tell me :)

[sndnvaps]

https://github.com/Tasssadar/multirom/pull/97/commits/52702946f1ab591d2fe48ee7df28312ca4298eb1

this change depend on you kernel

[sndnvaps]

+    #if (PLATFORM_SDK_VERSION >= 21)
+        ionAllocData.heap_id_mask =
+    #else

this not work for me , so i make my change to fit it ..

[z3ntu]

I meant, that this is a patch that only depends on the setting in the BoardConfig and not a if for every device that uses it (like you did in https://github.com/Tasssadar/multirom/pull/97/commits/52702946f1ab591d2fe48ee7df28312ca4298eb1)

[sndnvaps]

it just the patch for my device , but you can modified it to support more devie .