C2BufferTest: Get linear allocator as per device's capability

C2BufferTest must choose the correct linear allocator depending on the
whether the device supports ION on DMA-BUF heaps.

Test: atest C2BufferTest with and without CONFIG_ION enabled
Bug: 182117764
Change-Id: I9831487bf3eed7e6d5e512c5dd40eb0fe5efbbfb
1 file changed