bnxt_en: Remove usage of ulp_id

Since the driver continues to use the single ULP model,
the extra complexity and indirection is unnecessary.
Remove the usage of ulp_id from the code.

Suggested-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
Reviewed-by: Andy Gospodarek <andrew.gospodarek@broadcom.com>
Reviewed-by: Selvin Xavier <selvin.xavier@broadcom.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>