Incorect masking in the lifting for PPC sraw and srad instruction

<img width="756" height="313" alt="Image" src="https://github.com/user-attachments/assets/a421d104-a515-4591-9c17-d87ed78eeeb2" />

For reference:

1. https://fenixfox-studios.com/manual/powerpc/instructions/sraw.html
2. https://fenixfox-studios.com/manual/powerpc/instructions/srw.html