Revert "mlx5: move affinity hints assignments to generic code"

Before the offending commit, mlx5 core did the IRQ affinity itself,
and it seems that the new generic code have some drawbacks and one
of them is the lack for user ability to modify irq affinity after
the initial affinity values got assigned.

The issue is still being discussed and a solution in the new generic code
is required, until then we need to revert this patch.

This fixes the following issue:
echo <new affinity> > /proc/irq/<x>/smp_affinity
fails with  -EIO

This reverts commit a435393a.
Note: kept mlx5_get_vector_affinity in include/linux/mlx5/driver.h since
it is used in mlx5_ib driver.

Fixes: a435393a

 ("mlx5: move affinity hints assignments to generic code")
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jes Sorensen <jsorensen@fb.com>
Reported-by: Jes Sorensen <jsorensen@fb.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>