PurleyOpenBoardPkg/BoardMtOlympus: Drop the consume of 8259 PIC driver

The commit will:

A) Add explicit logic to disable the 8259 interrupts in BoardInitLib;
B) Remove the consumption of 8259 PIC driver from the DSC/FDF files for
   the BoardMtOlympus platform.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
Reviewed-by: Xiaohu Zhou <bowen.zhou@intel.com>