Note: at this time, the ssl module on pico_w never verifies the server
certificate. This means it does not actually provide a higher security
level than regular socket / http protocols.
A recent build failed. The original error seemed to be during ci_fetch_deps
where a build message said
```
fatal: reference is not a tree: 346c936e14c6ea3a8d3d65cb1fa46202dc92999d
fatal: Unable to checkout '346c936e14c6ea3a8d3d65cb1fa46202dc92999d' in submodule path 'extmod/ulab'
```
(along with other problems), but this step didn't signal failure to
github actions.
By adding the check= parameter, a failure of the subprocess will cause
a CalledProcessError to be raised, which will make ci_fetch_deps exit with
nonzero status. In turn, this should let Actions understand that something
went wrong with this step, instead of waiting for some subsequent step(s)
to go wrong.
This targets the 64-bit CPU Raspberry Pis. The BCM2711 on the Pi 4
and the BCM2837 on the Pi 3 and Zero 2W. There are 64-bit fixes
outside of the ports directory for it.
There are a couple other cleanups that were incidental:
* Use const mcu_pin_obj_t instead of omitting the const. The structs
themselves are const because they are in ROM.
* Use PTR <-> OBJ conversions in more places. They were found when
mp_obj_t was set to an integer type rather than pointer.
* Optimize submodule checkout because the Pi submodules are heavy
and unnecessary for the vast majority of builds.
Fixes#4314
