[media] ARM: DT: STi: stihxxx-b2120: Add pulse-width properties to ssc2 & ssc3

Adding these properties makes the I2C bus to the demodulators much
more reliable, and we no longer suffer from I2C errors when tuning.

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