dpaa2-switch: reduce the size of the if_id bitmap to 64 bits

The maximum number of DPAA2 switch interfaces, including the control
interface, is 64. Even though this restriction existed from the first
place, the command structures which use an interface id bitmap were
poorly described and even though a single uint64_t is enough, all of
them used an array of 4 uint64_t's.
Fix this by reducing the size of the interface id field to a single
uint64_t.

Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>