net/mlx4_en: Add dynamic variable to hold the number of user priorities (UP)

Until this patch, the number of UPs was hard coded for eight.
Replace this with a variable in struct "mlx4_en_port_profile".
Currently, the variable will hold the maximum number of UP,
as before.
The patch creates an infrastructure to add an option for dynamic
change of the actual number of TCs.

Signed-off-by: Inbar Karmy <inbark@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Cc: Tarick Bedeir <tarick@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>