[media] c8sectpfe: Add c8sectpfe debugfs support

Some basic debugfs support to dump the IP registers. Further
statistics could easily be added in the future for example for
each enabled tsin channel we could expose number of corrupt packets
received etc.

Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>