### Summary

When running `ansible -m setup host`, reported `ansible_memtotal_mb` fact changes between invocations.
That's because `setup` reads available non-kernel memory, which fluctuates:

https://github.com/ansible/ansible/blob/2797dc644aa8c809444ccac64cad63e0d9a3f9fe/lib/ansible/module_utils/facts/hardware/openbsd.py#L96-L97

To read total available memory, `hw.physmem` key should be used. Refer to the https://man.openbsd.org/sysctl.2 man, `HW_USERMEM` and `HW_PHYSMEM`.

### Issue Type

Bug Report

### Component Name

setup

### Ansible Version

```console
All.

https://github.com/ansible/ansible/blob/devel/lib/ansible/module_utils/facts/hardware/openbsd.py#L97
```


### Configuration

```console
N/A
```


### OS / Environment

OpenBSD 7.0

### Steps to Reproduce

On OpenBSD host, run this few times:

```
ansible -m setup openbsd_host | grep memtotal
```

Total memory value will be fluctuation between calls.

### Expected Results

I expect to see total installed memory.

### Actual Results

```console
N/A
```


### Code of Conduct

- [X] I agree to follow the Ansible Code of Conduct
sysctl_cmd = self.module.get_bin_path('sysctl')
        cmd = [sysctl_cmd, '-n', 'kern.boottime']
        rc, out, err = self.module.run_command(cmd)
        if rc != 0:
            return {}
        kern_boottime = out.strip()
        if not kern_boottime.isdigit():
            return {}
        return {
            'uptime_seconds': int(time.time() - int(kern_boottime)),
        }
    def get_processor_facts(self):
        cpu_facts = {}
        processor = []
        for i in range(int(self.sysctl['hw.ncpuonline'])):
            processor.append(self.sysctl['hw.model'])
        cpu_facts['processor'] = processor
        
        
        
        
        
        
        
        cpu_facts['processor_count'] = self.sysctl['hw.ncpuonline']
        cpu_facts['processor_cores'] = self.sysctl['hw.ncpuonline']
        return cpu_facts
    def get_device_facts(self):