drm/omap: dsi: Add missing IRQF_ONESHOT

fixed the following coccicheck:
./drivers/gpu/drm/omapdrm/dss/dsi.c:4329:7-27: ERROR: Threaded IRQ with
no primary handler requested without IRQF_ONESHOT

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Fixes: 4c1b935f ("drm/omap: dsi: move TE GPIO handling into core")
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1616492093-68237-1-git-send-email-yang.lee@linux.alibaba.com