OvmfPkg/PlatformPei: Skip various items for S3 resume

OvmfPkg/PlatformPei: Skip various items for S3 resume

We will not be running DXE on S3 resume, so we don't
need to do these initialization items:
 * Reserve EMU Variable memory range
 * Declare Firmware volumes
 * Add memory HOBs

v5:
 * Move MiscInitialization back to running on S3 resume

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15295 6f19259b-4bc3-4df7-8a09-765794883524