qed: Fix setting of Management bitfields

The management firmware HSI contains masks which are already
shifted to their right place, so QED_MFW_SET_FIELD() is clearing
incorrect fields by shifting the mask by the offset.

Luckily, today we set the fields in an incrementing order [so we're
not erasing any previously set fields], but this still needs fixing.

Signed-off-by: Tomer Tayar <Tomer.Tayar@cavium.com>
Signed-off-by: Yuval Mintz <Yuval.Mintz@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>