Fix CPU architecture check for x86_64.

Recently, the value of ro.build.cpu.abi for x86_64 system images
was changed from the invalid 'x86' to the correct 'x86_64'.

Unfortunately, this triggered a bug in vl-android.c where the value
is checked. This patch modifies the code to accept 'x86_64' as a
valid ABI value in emulator-x86 and emulator64-x86, and simplifies
the logic to make it easier to add support for more architectures
in the future.

BUG=none

Change-Id: I35001536e8bbd156b809fce1cceacefd47c5f845
1 file changed