AArch64: Make Binder and Parcel 64-bit compatible

Changes include
[x] Long is used to store native pointers

[x] Added new method obtain(long obj) to Parcel. Binder
    uses this method instead of obtain(int obj).

[x] obtain(int) has been changed to throw unsupported
    operation exception.

Change-Id: I408e0f2a24deb28c9277d86670653a51eb314266
Signed-off-by: Ashok Bhat <ashok.bhat@arm.com>
Signed-off-by: Craig Barber <craig.barber@arm.com>
Signed-off-by: Kévin PETIT <kevin.petit@arm.com>