IpmiFeaturePkg: FixUp FuctionPointer in gPeiIpmiTransportPpiGuid after MemoryDiscovered

Description:
Currently, a page fault (PF#) is observed when accessing the PEI_IPMI_TRANSPORT_PPI in the post-memory phase.
The cause of this problem is that the PPI does not migrated from temporary RAM to permanent RAM.

Solution:
Register a memory shadow handler in the PeiGenericIpmi PEIM that performs pointer fixes for PEI_IPMI_TRANSPORT_PPI after MemoryDiscovered.

Signed-off-by: Ning Feng <ning.feng@intel.com>