ravb: Support separate Line0 (Desc), Line1 (Err) and Line2 (Mgmt) irqs

R-Car has a combined interrupt line, ch22 = Line0_DiA | Line1_A | Line2_A.
RZ/V2M has separate interrupt lines for each of these, so add a feature
that allows the driver to get these interrupts and call the common handler.

Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>