spapr_pci: Fix unsafe signed/unsigned comparisons

spapr_pci: Fix unsafe signed/unsigned comparisons

spapr_pci.c contains a number of expressions of the form (uval == -1) or
(uval != -1), where 'uval' is an unsigned value.

This mostly works in practice, because as long as the width of uval is
greater or equal than that of (int), the -1 will be promoted to the
unsigned type, which is the expected outcome.

However, at least for the cases where uval is uint32_t, this would break
on platforms where sizeof(int) > 4 (and a few such do exist), because then
the uint32_t value would be promoted to the larger int type, and never be
equal to -1.

This patch fixes these errors.  The fixes for the (uint32_t) cases are
necessary as described above.  I've made similar fixes to (uint64_t) and
(hwaddr) cases.  Those are strictly theoretical, since I don't know of any
platforms where sizeof(int) > 8, but hey, it's not that hard so we might
as well be strictly C standard compliant.

Reported-by: Markus Armbruster <[email protected]>
Signed-off-by: David Gibson <[email protected]>
Reviewed-by: Markus Armbruster <[email protected]>
Signed-off-by: Alexander Graf <[email protected]>