WHENCE: use https://linuxtv.org for LinuxTV URLs

While https was always supported on linuxtv.org, only in
Dec 3 2015 the website is using valid certificates.

As we're planning to drop pure http support on some
future, change the http://linuxtv.org references at firmware/WHENCE
file to point to https://linuxtv.org instead.

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

firmware/WHENCE

@@ -677,7 +677,7 @@ File: av7110/bootcode.bin
 
 Licence: GPLv2 or later
 
-ARM assembly source code available at http://www.linuxtv.org/downloads/firmware/Boot.S
+ARM assembly source code available at https://linuxtv.org/downloads/firmware/Boot.S
 
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