By default, sparse assumes a 64bit machine when compiled on x86-64
and 32bit when compiled on anything else.

This can of course create all sort of problems, like issuing false
warnings like: 'constant ... is so big it is unsigned long long'
or 'shift too big (32) for type unsigned long' when the architecture
is 64bit while sparse was compiled on a 32bit machine, or worse,
to not emit legitimate warnings in the reverse situation.

Fix this by passing to sparse the appropriate -m32/-m64 flag.

To: Chris Metcalf <cmetcalf@mellanox.com>
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Signed-off-by: Chris Metcalf <cmetcalf@mellanox.com>