scripts/spelling.txt: add "swithc" pattern and fix typo instances

Fix typos and add the following to the scripts/spelling.txt:

  swithc||switch
  swithced||switched
  swithcing||switching

Link: http://lkml.kernel.org/r/1481573103-11329-3-git-send-email-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/media/i2c/adv7183_regs.h b/drivers/media/i2c/adv7183_regs.h
index 843d499..4ade89d 100644
--- a/drivers/media/i2c/adv7183_regs.h
+++ b/drivers/media/i2c/adv7183_regs.h
@@ -83,7 +83,7 @@
 #define ADV7183_LETTERBOX_3        0x9D /* Letterbox 3 */
 #define ADV7183_CRC_EN             0xB2 /* CRC enable */
 #define ADV7183_ADC_SWITCH_1       0xC3 /* ADC switch 1 */
-#define ADV7183_ADC_SWITCH_2       0xC4 /* ADC swithc 2 */
+#define ADV7183_ADC_SWITCH_2       0xC4 /* ADC switch 2 */
 #define ADV7183_LETTERBOX_CTRL_1   0xDC /* Letterbox control 1 */
 #define ADV7183_LETTERBOX_CTRL_2   0xDD /* Letterbox control 2 */
 #define ADV7183_SD_OFFSET_CB       0xE1 /* SD offset Cb */