missing pullups on system I2C bus

although the system I2C bus is not exposed to the exterior, its signals have to be declared and pullups put in place. Reason for this is, that the state machine responsible for reset of the I2C is expecting a value of 'H' or '1' on those two pins in order to continue the reset procedure. If not present, the simulation gets stuck on I2C reset, which as a side-effect makes the vme64x_core unresponsive.

This patch puts the pullups on I2C bus