Adds intrinsics for the following SME2 instructions:
- srshl (single, 2 & 4 vector)
- srshl (multi, 2 & 4 vector)
- urshl (single, 2 & 4 vector)
- urshl (multi, 2 & 4 vector)
NOTE: These intrinsics are still in development and are subject to future changes.