ShellPkg: BcfgDisplayDump(): fix reporting of OptionalData

ShellPkg: BcfgDisplayDump(): fix reporting of OptionalData

In this cleaned up form of BcfgDisplayDump(), it is easier to see that the

  OptionalDataOffset <= BufferSize

expression, used to report whether optional data are *absent*, is
incorrect. For any well-formed EFI_LOAD_OPTION, this inequality always
holds.

Optional data are present exactly if

  OptionalDataOffset < BufferSize

therefore the absence condition is the negation of the above,

  OptionalDataOffset >= BufferSize

This patch fixes the bug where BCFG always reports "Optional- N", even if
optional data exist.

Cc: Jaben Carsey <jaben.carsey@intel.com>
Cc: Ryan Harkin <ryan.harkin@linaro.org>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jaben Carsey <jaben.carsey@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@19715 6f19259b-4bc3-4df7-8a09-765794883524