drm/i195: Rename gt_irq_handler variable

Renamed tmp variable to the more descriptive iir. (Daniel Vetter/
Thomas Daniel)

Issue: VIZ-4277
Signed-off-by: Nick Hoath <nicholas.hoath@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Gordon <david.s.gordon@intel.com>
Cc: Thomas Daniel <thomas.daniel@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1445333036-22164-2-git-send-email-nicholas.hoath@intel.com


Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>