Corrected syntax of v_interp_*_f16 opcodes to match sp3; added missing v_interp_*_f32_e64 opcodes.
See bug 32621: https://bugs.llvm.org//show_bug.cgi?id=32621
Known issues (postponed):
- non-vop3 v_interp opcodes are disassembled incorrectly (should have "_e32" suffix);
- there are subtle changes in gfx9 affecting v_interp_p2_f16; this will be accounted for at a later time.