ibmveth: use consistent types

These variables are only used with an interface that just dumps their
values into registers to be passed to the hypervisor. The arguments
to that interface are declared to be "unsigned long", so make these
variables match.  The macros are only used with these variables, so make
them match as well.

This code is currently only built for 64bit powerpc, so the transformation
is really a noop.  If the interface was ever ported to 32 bit, it would
almost certainly still use registers to pass the parameters and so
"unsigned long" would still be appropriate.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>