qtscript: Add support for MIPS64 platforms

This fix do not apply to Qt 5 because qtscript has been already patched
in 408847dcdfe1d407cd85616e8f595fb5ea25ca46

Task-number: QTBUG-35030

Change-Id: I0eb71aa875afef9eee15a203b9bd24f5395a3463
Signed-off-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Reviewed-by: YunQiang Su <wzssyqa@gmail.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>