ice: clear VF ARQLEN register on reset

On older devices like X710 and X722, the VF's ARQLEN register is cleared
on reset, so the VF driver uses that register to detect an unannounced
reset. Unfortunately, on devices controlled by ice, this register is NOT
cleared on reset. This causes the VF to miss resets, and even on
properly-announced resets, the VF driver complains that it didn't see
the reset.

To fix this, we'll do it in software. When we handle a VF reset (whether
triggered by software or VFLR), clear this register after the HW reset
is complete.

Signed-off-by: Mitch Williams <mitch.a.williams@intel.com>
Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>