ACPI, APEI, EINJ Allow empty Trigger Error Action Table

According to the ACPI spec [1] section 18.6.4 the TRIGGER_ERROR action
table can consists of zero elements.

[1] Advanced Configuration and Power Interface Specification
    Revision 5.0, December 6, 2011
	http://www.acpi.info/DOWNLOADS/ACPIspec50.pdf



Signed-off-by: Niklas Söderlund <niklas.soderlund@ericsson.com>
Acked-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>