mlxbf_pmc: bring in latest 6.8 upstream commits

[David Thompson]

SRU Justification:

[Impact]

There are currently five upstream commits for Nvidia's mlxbf_pmc driver
that are present in upstream, but not in the NV-Kernels 24.04 repo. These five
commits provide several important fixes and a patch for style cleanup.

[Fix]

Cherry pick the following five commits from upstream linux:
Dan Carpenter 7c8772fef2c2 platform/mellanox: mlxbf-pmc: fix signedness bugs
Luiz Capitulino c0459eeb64e9 platform/mellanox: mlxbf-pmc: Ignore unsupported performance blocks
Luiz Capitulino 0d46439bda37 platform/mellanox: mlxbf-pmc: mlxbf_pmc_event_list(): make size ptr optional
Shravan Kumar Ramani 1ae9ffd303c2 platform/mellanox: mlxbf-pmc: Cleanup signed/unsigned mix-up
Shravan Kumar Ramani fd23023e2aaa platform/mellanox: mlxbf-pmc: Replace uintN_t with kernel-style types

[Test Cases]

* Verify mlxbf_pmc driver loads properly on BlueField-2 and BlueField-3 platforms
* Exercise mlxbf_pmc driver functionality via sysfs reads and writes.