Removed the assumption on APIC timer initial Count is all 1s and updated it to handle the long delay that timer initial count.

Signed-off-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>

git-svn-id: svn://svn.code.sf.net/p/edk2/code/trunk/edk2/MdePkg@14603 6f19259b-4bc3-4df7-8a09-765794883524