net: ravb: Move getting/requesting IRQs in the probe() method

The runtime PM implementation will disable clocks at the end of
ravb_probe(). As some IP variants switch to reset mode as a result of
setting module standby through clock disable APIs, to implement runtime PM
the resource parsing and requesting are moved in the probe function and IP
settings are moved in the open function. This is done because at the end of
the probe some IP variants will switch anyway to reset mode and the
registers content is lost. Also keeping only register settings operations
in the ravb_open()/ravb_close() functions will make them faster.

Commit moves IRQ requests to ravb_probe() to have all the IRQs ready when
the interface is open. As now getting/requesting IRQs is done in a single
place there is no need to keep intermediary data (like ravb_rx_irqs[] and
ravb_tx_irqs[] arrays or IRQs in struct ravb_private).

In order to avoid accessing the IP registers while the IP is runtime
suspended (e.g. in the timeframe b/w the probe requests shared IRQs and
IP clocks are enabled) in the interrupt handlers were introduced
pm_runtime_active() checks. The device runtime PM usage counter has been
incremented to avoid disabling the device's clocks while the check is in
progress (if any).

This is a preparatory change to add runtime PM support for all IP variants.

Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>