[media] TM6000: Clean-up i2c initialization

Usage of templates for large structures is a bad idea, as it wastes a
lot of space. Manually initializing the few fields we need is way more
efficient.

Also set the algorithm data const, use strlcpy instead of strcpy, fix
a small race (device data must always be set before registering said
device) and properly return error on adapter registration failure.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Michel Ludwig <michel.ludwig@gmail.com>
Cc: Stefan Ringel <stefan.ringel@arcor.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>