Add FP arithmetic events

[bcstrongx]

From Bruce's email:
INST.FP.LOAD.RET
INST.FP.STORE.RET
INST.FP.ADD.RET
INST.FP.MULTIPLY.RET
INST.FP.FUSED-MULTIPLY-ADD.RET
INST.FP.DIVIDE-SQRT.RET
INST.FP.OTHER.RET

[bcstrongx]

See discussion in this thread: https://lists.riscv.org/g/tech-performance-events/topic/111926105

[mattdturner]

Can the FP instructions be split based on precision (e.g., single vs double)?

[bcstrongx]

In May 1, 2025, meeting, agreed to count FP insts and vector elements, with breakdown per-precision. This should allow for counting TOPS and FLOPS.