MdeModulePkg/PeiCore: Remove MigrateSecModulesInFv()

MdeModulePkg/PeiCore: Remove MigrateSecModulesInFv()

REF:https://bugzilla.tianocore.org/show_bug.cgi?id=3564

This function has not been called since it was added in commit
9bedaec. If the function were to remain, it would need to be
re-evaluated and tested. This change removes the function since
it is not being used.

Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Hao A Wu <hao.a.wu@intel.com>
Cc: Dandan Bi <dandan.bi@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Debkumar De <debkumar.de@intel.com>
Cc: Harry Han <harry.han@intel.com>
Cc: Catharine West <catharine.west@intel.com>
Cc: Marvin H?user <mhaeuser@posteo.de>
Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>
Reviewed-by: Hao A Wu <hao.a.wu@intel.com>