ion: Remove ION_HEAP_FLAG_DEFER_FREE for dynamic carveout heaps

Dynamic carveout heaps can have their memory removed immediately
after all of its memory is no longer in use. However, the
deferred free mechanism that carveout heaps use can cause immediate
removal of heap memory to fail. Thus, do not use the
ION_HEAP_FLAG_DEFER_FREE flag for dynamic carveout heaps.

Change-Id: I2e4edd130cad9f1361b88210e69cf24cb0f271bb
Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>