cxgb4: Fix static checker warning

The patch e85c9a7a: ("cxgb4/cxgb4vf: Add code to calculate T5 BAR2
Offsets for SGE Queue Registers") from Dec 3, 2014, leads to the
following static checker warning:

        drivers/net/ethernet/chelsio/cxgb4/t4_hw.c:5358
	t4_bar2_sge_qregs()
        warn: should '(qid >> qpp_shift) << page_shift' be a 64 bit type?

This patch fixes it

Signed-off-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>