Fix type of loop variable in alloc_device().

[Gerald Pfeifer]

On Fri, 2 Nov 2007, Vitaliy Margolen wrote:
>> We iterate between 0 and and the value of an usigned variable, so we
>> should adjust the loop variable accordingly (not the list to silence
>> GCC).
>
>> -    int i;
>> +    unsigned i;
> If there is nothing wrong about it, then why do you change it? If even gcc
> does not complain about it.

More recent versions of GCC do. ;-)

And while in many cases these warnings do not indicate a real problem,
in some they do (and we found just one such real problem yesterday).

Gerald