Whether Premiere Pro can use two Tesla P40 graphics for hardware acceleration?

Premiere Pro cannot fully utilize more than one single GPU. Or put it this way, the performance improvement with two identical GPUs over a single one is nowhere near enough to justify the high additional cost. In the worst cases, a system with two GPUs perform equal to or slower than that same PC with only one GPU.

Now, if you were using Davinci Resolve Studio (the paid version), then yes, the second GPU would have been justifiable.

Also, all of those GPUs are based on a now-three-generation-old Pascal architecture, which has not aged well at all over the seven years since it was introduced. In fact, in Premiere Pro all three of your GPUs combined perform significantly slower than just one single recent-gen Ampere GPU that's relatively high-end.

And starting with the Ampere generation, NVIDIA retired both the Quadra and Tesla product branding, and instead now simply calls them NVIDIA Workstation GPUs and NVIDIA Data Center GPUs, respectively.

@RjL190365  can you answer?