APMXGenePkg:ACPI: Fix parsing MAC and mapping CSR region

From: Tuan Phan <tphan@apm.com>

This patch makes default MAC address not zero to make ASL not
convert to none data type as we expect it should be interger.
Also fix mapping CSR fail when multi node sharing same memory region.

Signed-off-by: Tuan Phan <tphan@apm.com>