bnxt_en: Reduce BNXT_MSIX_VEC_MAX value to supported CQs per PF.

Broadcom adapters support only maximum of 512 CQs per PF. If user sets
MSIx vectors more than supported CQs, firmware is setting incorrect value
for msix_vec_per_pf_max parameter. Fix it by reducing the BNXT_MSIX_VEC_MAX
value to 512, even though the maximum # of MSIx vectors supported by adapter
are 1280.

Fixes: f399e849 ("bnxt_en: Use msix_vec_per_pf_max and msix_vec_per_pf_min devlink params.")
Signed-off-by: Vasundhara Volam <vasundhara-v.volam@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>