Mellanox: Add new mlxsw_spectrum firmware xx.2008.2304

Add latest verified version of Mellanox Spectrum-family switch firmware,
for Spectrum (13.2008.2304), Spectrum-2 (29.2008.2304) and Spectrum-3
(30.2008.2304).

This release fixes the following issues (among others):

- Rx pause packet reaction latency on Spectrum-3
- Certain high-numbered flow counters would not work on Spectrum-2.
- FW freeze on Spectrum-1 when under heavy PTP traffic load.
- Mirroring traffic to the CPU on Spectrum-2.
- Shared headroom would not be exhausted before drops started occurring.
- Per-priority Rx discard counters were not always cleared.
- 400-Gbps ports with PFC enabled kept sending pause frames without buffer
  pressure.
- Several issues in flow control and traffic admittance, and FW freeze
  after an on-the-fly shared buffer reconfiguration.
- A number of issues in forwarding line speed traffic to partially split
  8x ports on Spectrum-3.
- A number of issues related to in-service FW upgrade (ISSU / ISFU).
- Port shaper influenced ingress rate when PFC was enabled.
- FW freeze after a port was set admin down when unrelated ports were
  congested.

And includes the following new feature:

- Improvements to counter read performance

Signed-off-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Josh Boyer <jwboyer@kernel.org>