net/mlx5: E-switch, Use PF num in metadata reg c0

Currently only 256 vports can be supported as only 8 bits are
reserved for them and 8 bits are reserved for vhca_ids in
metadata reg c0. To support more than 256 vports, replace
vhca_id with a unique shorter 4-bit PF number which covers
upto 16 PF's. Use remaining 12 bits for vports ranging 1-4095.
This will continue to generate unique metadata even if
multiple PCI devices have same switch_id.

Signed-off-by: sunils <sunils@nvidia.com>
Reviewed-by: Parav Pandit <parav@nvidia.com>
Reviewed-by: Vu Pham <vuhuong@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>