drm/xe/vf: Don't touch GuC irq registers if using memory irqs

On platforms where VFs are using memory based interrupts, we
missed invalid access to no longer existing interrupt registers,
as we keep them marked with XE_REG_OPTION_VF. To fix that just
either setup memirq vectors in GuC or enable legacy interrupts.

Fixes: aef4eb7c ("drm/xe/vf: Setup memory based interrupts in GuC")
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240617154736.685-1-michal.wajdeczko@intel.com