qlge: Allow running MSIx with fewer vectors.

Currently we downshift to MSI/Legacy if we don't get enough vectors for
cpu_count RSS rings plus cpu_count TX completion rings.  This patch
allows running MSIX with the vector count that the platform provides.

Signed-off-by: Ron Mercer <ron.mercer@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>