No need to try mmap path when the vendor property set as NEVER.

When the vendor set the MMAP policy as NEVER, the AAudioService will not
be created. In that case, there is no need to try MMAP path as it will
always fail.

Bug: 242103542
Test: repo steps in the bug
Test: atest AAudioTests
Change-Id: Ia34153bc1464e059f8b65865b4fcb6f83b3a160d