ANDROID: GKI: Fix file mode on mtk abi file

Remove executable bit on abi_gki_aarch64_mtk file.

This file was added in 55d7c4ec, the mode of
abi_gki_aarch64.xml was fixed in eb02ea0e, this
patch fixes the other file that from the
55d7c4ec patch.

Bug: 149040612
Fixes: 55d7c4ec ("ANDROID: Update symbol list for mtk")
Signed-off-by: Pat Tjin <pattjin@google.com>
Change-Id: I3800136eb7d7f54a89508660ae40e662ee5ac571