OvmfPkg: resolve PcdLib for PEIMs to PeiPcdLib by default

In the previous patch we had to add two explicit Null resolutions, but
here we can remove five PeiPcdLib ones, after setting the default to it.

Cc: Jordan Justen <jordan.l.justen@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

OvmfPkg/OvmfPkgIa32X64.dsc

@@ -261,6 +261,7 @@
   CpuExceptionHandlerLib|UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiCpuExceptionHandlerLib.inf
   MpInitLib|UefiCpuPkg/Library/MpInitLib/PeiMpInitLib.inf
   QemuFwCfgS3Lib|OvmfPkg/Library/QemuFwCfgS3Lib/PeiQemuFwCfgS3LibFwCfg.inf
+  PcdLib|MdePkg/Library/PeiPcdLib/PeiPcdLib.inf
 
 [LibraryClasses.common.DXE_CORE]
   HobLib|MdePkg/Library/DxeCoreHobLib/DxeCoreHobLib.inf
@@ -575,32 +576,19 @@
     <LibraryClasses>
       PcdLib|MdePkg/Library/BasePcdLibNull/BasePcdLibNull.inf
   }
-  MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf {
-    <LibraryClasses>
-      PcdLib|MdePkg/Library/PeiPcdLib/PeiPcdLib.inf
-  }
+  MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf
 
-  OvmfPkg/PlatformPei/PlatformPei.inf {
-    <LibraryClasses>
-      PcdLib|MdePkg/Library/PeiPcdLib/PeiPcdLib.inf
-  }
+  OvmfPkg/PlatformPei/PlatformPei.inf
   UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume2Pei.inf {
     <LibraryClasses>
-      PcdLib|MdePkg/Library/PeiPcdLib/PeiPcdLib.inf
 !if $(SMM_REQUIRE) == TRUE
       LockBoxLib|MdeModulePkg/Library/SmmLockBoxLib/SmmLockBoxPeiLib.inf
 !endif
   }
 !if $(SMM_REQUIRE) == TRUE
-  OvmfPkg/SmmAccess/SmmAccessPei.inf {
-    <LibraryClasses>
-      PcdLib|MdePkg/Library/PeiPcdLib/PeiPcdLib.inf
-  }
+  OvmfPkg/SmmAccess/SmmAccessPei.inf
 !endif
-  UefiCpuPkg/CpuMpPei/CpuMpPei.inf {
-    <LibraryClasses>
-      PcdLib|MdePkg/Library/PeiPcdLib/PeiPcdLib.inf
-  }
+  UefiCpuPkg/CpuMpPei/CpuMpPei.inf
 
 [Components.X64]
   #