opal-elog-parse: Add function file_filter to assist retrieving directory contents
opal-elog-parse: Add function file_filter to assist retrieving directory contents

Signed-off-by: Samuel Mendoza-Jonas <f16bed56189e249fe4ca8ed10a1ecae60e8ceac0@ozlabs.au.ibm.com>
Reviewed-by: Stewart Smith <ec31ab75ddf977353c8f660f92ea8b23f64aef25@linux.vnet.ibm.com>

leitao/ppc64-diag,leitao/ppc64-diag,leitao/ppc64-diag,leitao/ppc64-diag