AArch64: List arm64 as instruction set option

When arm64 was added to dex2oat, it wasn't added to the list of
instruction sets in the help text. This adds it.

Change-Id: I9ffecb67a053b24ad624effd1853ff47331d2e91
Signed-off-by: Stuart Monteith <stuart.monteith@arm.com>
1 file changed