drm/exynos: fix incorrect type issue

Fix incorrect type issue in fimd_commit() of exynos_drm_fimd.c module.
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202312140930.Me9yWf8F-lkp@intel.com/Signed-off-by: Inki Dae <inki.dae@samsung.com>

drivers/gpu/drm/exynos/exynos_drm_fimd.c

@@ -480,7 +480,7 @@ static void fimd_commit(struct exynos_drm_crtc *crtc)
 	struct fimd_context *ctx = crtc->ctx;
 	struct drm_display_mode *mode = &crtc->base.state->adjusted_mode;
 	const struct fimd_driver_data *driver_data = ctx->driver_data;
-	void *timing_base = ctx->regs + driver_data->timing_base;
+	void __iomem *timing_base = ctx->regs + driver_data->timing_base;
 	u32 val;
 
 	if (ctx->suspended)