Documentation: sound/cards: fix heading underline lengths for https: changes

Fix documentation build warnings for underline length too short,
caused by s/http/https/ and not changing the accompanying underlines.

Documentation/sound/cards/audigy-mixer.rst:335: WARNING: Title underline too short.
US Patents (https://www.uspto.gov/)
----------------------------------

Documentation/sound/cards/sb-live-mixer.rst:340: WARNING: Title underline too short.
US Patents (https://www.uspto.gov/)
----------------------------------

Fixes: 7ed33ea6b4 ("ALSA: Replace HTTP links with HTTPS ones")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Alexander A. Klimov <grandmaster@al2klimov.de>
Link: https://lore.kernel.org/r/357ee576-32a2-6e2b-1db6-78be39253846@infradead.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>

Documentation/sound/cards/audigy-mixer.rst

@@ -332,7 +332,7 @@ WO 9901953 (A1)
 
 
 US Patents (https://www.uspto.gov/)
-----------------------------------
+-----------------------------------
 
 US 5925841
 	Digital Sampling Instrument employing cache memory (Jul. 20, 1999)

Documentation/sound/cards/sb-live-mixer.rst

@@ -337,7 +337,7 @@ WO 9901953 (A1)
 
 
 US Patents (https://www.uspto.gov/)
-----------------------------------
+-----------------------------------
 
 US 5925841
 	Digital Sampling Instrument employing cache memory (Jul. 20, 1999)