net: thunderx: nicvf_queues: nivc_*_intr: remove duplication

The same switch-case repeates for nivc_*_intr functions.
In this patch it is moved to a helper nicvf_int_type_to_mask().

By the way:
 - Unneeded write to NICVF register dropped if int_type is unknown.
 - netdev_dbg() is used instead of netdev_err().

Signed-off-by: Yury Norov <yury.norov@auriga.com>
Signed-off-by: Aleksey Makarov <aleksey.makarov@caviumnetworks.com>
Acked-by: Vadim Lomovtsev <Vadim.Lomovtsev@caiumnetworks.com>
Signed-off-by: Sunil Goutham <sgoutham@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>