MdeModulePkg/DisplayEngine: Return the selectable menu correctly

MdeModulePkg/DisplayEngine: Return the selectable menu correctly

When returning selectable menu, should return the menu in current form,
the codes miss to do the check. Now returning the selectable menu behind
the codes "if ((UINTN) Distance + NextMenuOption->Skip > GapToTop)".
Then can cover the check, can return the menu correctly.

https://bugzilla.tianocore.org/show_bug.cgi?id=232

Cc: Liming Gao <liming.gao@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Dandan Bi <dandan.bi@intel.com>
Reviewed-by: Eric Dong <eric.dong@intel.com>