Summarise bad block printk output

Reduces the amount of time the unit takes when booting with serial output
Reduce YAFFS output of startup bad blocks

The kernel already displays most of this, so it's just repetition
Add support to control TX enable lines externally
Export EP93xx UART structures

Allows us to add board specific function pointers
Re-order ep93xx_eth driver

Makes it more similar to mainline for backporting future updates