[spi_host,dv] Resolve open DV TODOs (post M2.5)

[hcallahan-lowrisc]

Description

The PR https://github.com/lowRISC/opentitan/pull/18887 captures the outstanding TODOs against this issue.

• [ ] V3 https://github.com/lowRISC/opentitan/pull/18887/commits/68220c1a7c6698f584b28c06a54664ea3cfb3bef#diff-6b99091a0adff92907312eede55ddee498e4c65c3a113783dab57328f489fc2fR10 : Captures the fact that we currently only perform verification against NUM_CS=1 (single CSB).
• [ ] V3 https://github.com/lowRISC/opentitan/pull/18887/commits/68220c1a7c6698f584b28c06a54664ea3cfb3bef#diff-efe52f816c8593e255e91c8bbf9ae1f0fd702d5927d037e9ef93d008328ef1c9R36 : Captures that the stress_tests.hjson generic testcases have not yet been enabled, but this is a V3 task.
• [ ] V3 All other items constitute testbench improvements that are nice-to-have.

[msfschaffner]

Closing since SPI_HOST has been signed off. Please re-open if that is not accurate.

[andreaskurth]

Reopening as the TODOs that refer to this issue still exist in master. Reassigning to M2.5 Backlog as the TODOs don't have to be resolved for M2.5 AFAIK.

[msfschaffner]

SG - thanks @andreaskurth!

[moidx]

Only NUM_CS=1 is supported in the version of the block integrated into Earlgrey-PROD.

@hcallahan-lowrisc to align documentation.