ShellPkg: Fix pci command for '_e' option Processing of '_e' argument was missing. Added fix, to process the '_e' option for printing additional AER information. Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Abdul Lateef Attar <abdul-lateef.attar@hpe.com> Reviewed-by: Jaben Carsey <jaben.carsey@intel.com> Reviewed-by: Qiu Shumin <shumin.qiu@intel.com>