PcAtChipsetPkg: Remove framework modules

PcAtChipsetPkg: Remove framework modules

REF:https://bugzilla.tianocore.org/show_bug.cgi?id=1844

The commit will remove the below modules from PcAtChipsetPkg:
* PcAtChipsetPkg/8259InterruptControllerDxe/8259.inf
* PcAtChipsetPkg/8254TimerDxe/8254Timer.inf
* PcAtChipsetPkg/IsaAcpiDxe/IsaAcpi.inf

They are considered legacy framework components and will no longer be used
after the removal of IntelFramework[Module]Pkg.

Also, the unused (after the modules being removed) PCDs will be deleted in
package level DEC/UNI files.

Cc: Andrew Fish <afish@apple.com>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Signed-off-by: Hao A Wu <hao.a.wu@intel.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>