MdeModulePkg/BMMUI: Remove the incorrect and useless codes

MdeModulePkg/BMMUI: Remove the incorrect and useless codes

When updating console page, the "ConsoleCheck" in BmmFakeNvData may maintain
the old uncommitted data, we should not copy it to BmmOldFakeNVData.
And in BootMaintRouteConfig function, when save data successfully,
it will copy the BmmFakeNvData to the BmmOldFakeNVData.
So we can delete the logic here.

Cc: Laszlo Ersek <lersek@redhat.com>
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>