drm/i915/bios: rewrite sequence block parsing

Make everything a bit more readable and clear.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/e8f2a62d78d90981a6b49fdf9ab3594f60a46033.1450702954.git.jani.nikula@intel.com
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index cf7e0fc..c6dd4db 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1477,7 +1477,7 @@
 		u8 seq_version;
 		u32 size;
 		u8 *data;
-		u8 *sequence[MIPI_SEQ_MAX];
+		const u8 *sequence[MIPI_SEQ_MAX];
 	} dsi;
 
 	int crt_ddc_pin;