Resolves several issues in UefiCpuPkg related to:
1. Unchecked returns leading to potential NULL or uninitialized access.
2. Potential unchecked integer overflows.
3. Incorrect comparison between integers of different sizes.
Co-authored-by: kenlautner <85201046+kenlautner@users.noreply.github.com>
Signed-off-by: Chris Fernald <chfernal@microsoft.com>