Simple fixes to the arguments to CAST and RESCALE

- The input/output types for CAST should be in_t* and out_t*
- The shape for the multiplier and shift arguments to RESCALE was in the wrong column

Change-Id: I0a3c4ffed15e36f0c4bf8fc9b4a84df5a17a5523
Signed-off-by: Kevin Petit <kevin.petit@arm.com>