OvmfPkg: Removing ipf which is no longer supported from edk2.

OvmfPkg: Removing ipf which is no longer supported from edk2.

Removing rules for Ipf sources file:
* Remove the source file which path with "ipf" and also listed in
  [Sources.IPF] section of INF file.
* Remove the source file which listed in [Components.IPF] section
  of DSC file and not listed in any other [Components] section.
* Remove the embedded Ipf code for MDE_CPU_IPF.

Removing rules for Inf file:
* Remove IPF from VALID_ARCHITECTURES comments.
* Remove DXE_SAL_DRIVER from LIBRARY_CLASS in [Defines] section.
* Remove the INF which only listed in [Components.IPF] section in DSC.
* Remove statements from [BuildOptions] that provide IPF specific flags.
* Remove any IPF sepcific sections.

Removing rules for Dec file:
* Remove [Includes.IPF] section from Dec.

Removing rules for Dsc file:
* Remove IPF from SUPPORTED_ARCHITECTURES in [Defines] section of DSC.
* Remove any IPF specific sections.
* Remove statements from [BuildOptions] that provide IPF specific flags.

Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Chen A Chen <chen.a.chen@intel.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>