EmulatorPkg/AutoScanPei: Report the correct CPU address size

EmulatorPkg/AutoScanPei: Report the correct CPU address size

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1119

Today's implementation reports CPU address size as 36 through CPU
HOB. But when WinHost is running at 64bit, the system memory might
be allocated above 2^36.

It causes system asserts when DxeCore code tries to find the
corresponding GCD entry for a given valid address.

The patch uses 57 as the CPU address size which is maximum linear
address size when 5-level paging is enabled in host OS.

Using 64 seems more proper and a one-time change even 6-level
paging might be invented. But it causes CoreInitializeGcdServices()
assertion on following code:
  Entry->EndAddress = LShiftU64 (1, SizeOfMemorySpace) - 1;
Because LShiftU64 expects SizeOfMemorySpace < 64.

So to be practical, I didn't report 64 and change
CoreInitializeGcdServices().

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Reviewed-by: Hao Wu <hao.a.wu@intel.com>
Cc: Andrew Fish <afish@apple.com>