ShellPkg: Update pci command to use ShellPrintEx()
- Also minor simplification to the PciPrintClassCode() function.
- Remove invalid duplicate gShellDebug1HiiHandle argument in STR_PCI_NO_FIND print.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Chris Phillips <chrisp@hp.com>
Reviewed-by: Jaben Carsey <jaben.carsey@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@14880 6f19259b-4bc3-4df7-8a09-765794883524