[earlgrey,conn] Connectivity checks in Jasper currently fail with a combinatorial loop

### Description

The connectivity checks for `top_earlgrey` currently fail because Jasper reports several combinatorial loops.

After a very quick triage, it looks a lot like the connectivity check is thinking about a situation where pinmux has been configured so that a SPI line is both an input and is also being driven (with a value based on that input).

Start with the top_earlgrey connectivity checks in Jasper and investigate the reported combinatorial loops around pinmux-configured SPI lines. Reproduce the failure, determine how the input and driven value interact, and verify that the connectivity checks complete without combinatorial-loop errors.

Written by the indexing model from the issue text.