MLBEDSW-10896: Add int64 type for Add operator
Changed to allow int64 type for Add as the cast operator which supports int64 output (with reinterpret cast) is converted to an Add.
Change-Id: I1b84a5fd34e8f258588a2bd7f6603d36c5ff0e88 Signed-off-by: Max Bergfelt max.bergfelt@arm.com