I2C1: no pull-ups

[jmatyas]

There are no pull-up resistors for I2C1 bus, and while it is OK when working with external controller (such as Kasli), it may be problematic when working in a standalone mode.

[kaolpr]

IS or MAY be a problem?

Note that in Sinara pull-ups are present on controller, so adding another on peripheral may lead to problems. Let's first identify if we really need those.