qed: Fix bitmap_weight() check

Fix the condition which verifies that only one flag is set. The API
bitmap_weight() should receive size in bits instead of bytes.

Fixes: b5a9ee7c ("qed: Revise QM cofiguration")
Signed-off-by: Denis Bolotin <denis.bolotin@cavium.com>
Signed-off-by: Michal Kalderon <michal.kalderon@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>