On serial TS mode output pin could be selected from D0 or D7.
Add configuration option to for it.

Rename TS mode config option prefix from AF9013_TS_ to AF9013_TS_MODE_.
Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>