OvmfPkg/MemEncryptSevLib: Make the MemEncryptSevLib available for SEC
    
    BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3108
    
    In preparation for a new interface to be added to the MemEncryptSevLib
    library that will be used in SEC, create an SEC version of the library.
    
    This requires the creation of SEC specific files.
    
    Some of the current MemEncryptSevLib functions perform memory allocations
    which cannot be performed in SEC, so these interfaces will return an error
    during SEC. Also, the current MemEncryptSevLib library uses some static
    variables to optimize access to variables, which cannot be used in SEC.
    
    Cc: Jordan Justen <jordan.l.justen@intel.com>
    Cc: Laszlo Ersek <lersek@redhat.com>
    Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
    Cc: Brijesh Singh <brijesh.singh@amd.com>
    Acked-by: Laszlo Ersek <lersek@redhat.com>
    Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
    Message-Id: <bc7fa76cc23784ab3f37356b6c10dfec61942c38.1610045305.git.thomas.lendacky@amd.com>