omapfb: fix typo

Fix spelling mistake: "lenght" -> "length"
Signed-off-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

drivers/video/fbdev/omap2/omapfb/dss/hdmi4_core.c

@@ -712,7 +712,7 @@ int hdmi4_audio_config(struct hdmi_core_data *core, struct hdmi_wp_data *wp,
 	else
 		acore.i2s_cfg.justification = HDMI_AUDIO_JUSTIFY_RIGHT;
 	/*
-	 * The I2S input word length is twice the lenght given in the IEC-60958
+	 * The I2S input word length is twice the length given in the IEC-60958
 	 * status word. If the word size is greater than
 	 * 20 bits, increment by one.
 	 */