Enable and fix error log variable_buffer support.
Enable and fix error log variable_buffer support.

Errorlog support for the fapi2::variable_buffer type was not enabled in
hostboot. Tests showed that when enabled, variable_buffer data was not
being propagated properly to the error log. The issue was found to be
that the pointer to the variable_buffer's internal data was not being
properly passed to an ffdc_t object. Also, transferring the size of
the variable_buffer data was not being correctly communicated to an
ffdc_t object because a specialization of the getErrorInfoFfdcSize
template function is needed. Becuase the specialization of the
getErrorInfoFfdcSize function with an ffdc_t parameter did not exist,
the code base used the primary function template for the
getErrorInfoFfdcSize function which just returns the size of an ffdc_t
object passed to it instead of the size of the contained data within
the ffdc_t.

Changes:
* Added specialization of getErrorInfoFfdcSize for fapi2::ffdc_t.
* Enabled variable_buffer support in parseErrorInfo.mk.
* Added const overload of the pointer() method for the fapi2::buffer
  and fapi2::variable_buffer classes. This to allow these methods
  to be used in the set_BUFFER methods that take a const reference
  to objects of these classes.
* Modified parseErrorInfo.pl to generate code to use the above
  mentioned pointer methods. The adjusted generated code fixes
  the problem of assigning an incorrect buffer pointer.

Change-Id: I20e1a1f83d611dacbb82ca14ee40bd436888ba0a
Original-Change-Id: I96dc89fbb68ee6a153ca43191181c56804b84ae8
RTC: 175239
Reviewed-on: http://ralgit01.raleigh.ibm.com/gerrit1/41541
Tested-by: Jenkins Server <8e3f934e4c44875bc48d33da3ea13d93ba9a233f@us.ibm.com>
Tested-by: PPE CI <dc75934ba5befb9221434e67a247b93aec46b36b@us.ibm.com>
Tested-by: Hostboot CI <52521565bd8ea18a2b112942dce4f4220a97c2c8@us.ibm.com>
Reviewed-by: William G. Hoffa <7dd6aa5e78423995d9d7c7ecada5b77ee07f88cc@us.ibm.com>
Reviewed-by: Richard J. Knight <94c04f3910596886be97211d492ad29f0ba29cd5@us.ibm.com>
Reviewed-by: Prachi Gupta <25a72946fc4ec2539bba3cff1fbb2916af6a7649@us.ibm.com>

open-power/hostboot,open-power/hostboot,open-power/hostboot,open-power/hostboot,open-power/hostboot