ACPICA: acpidump: Reduce freopen() invocations to improve portability

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>