Fix arm64 bug introduced by refactoring.

- Commit 1d8cdbc5202378 made changes to the parameters for
artSet64InstanceFromCode, but did not change THREE_ARG_DOWNCALL
to THREE_ARG_REF_DOWNCALL for arm64.

Change-Id: If256b0bd32dbd1c95f61e0afcb35975bb09a8b97
Signed-off-by: Stephen Kyle <stephen.kyle@arm.com>
1 file changed