This patch reduces the requirement of invoking freopen() in acpidump in order
to reduce the porting effort of acpidump.

This patch achieves this by turning all acpi_os_printf(stdout) into
acpi_ut_file_printf(gbl_output_file). Lv Zheng.
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>