Increase CPU timer frequency

Increase the frequency of the CPU timer to a more sane value of 50Hz
Add OpenCores KB device

Add simulation for the OpenCores keyboard device. It's a simple device
that just forwards qemu keycodes to the system
Add OpenCores framebuffer device

Add support for basic OpenCores framebuffer device with simple bpp and
direct rendering(no palette or dificult geometry)
Add ATA/IDE support for OpenRisc

Add ATA/IDE support for OpenRisc machine, including fix for ide mmio
device endianess
Not specifing a IDE device will not fail the emulator
Enable framebuffer in OpenRisc config

Make sure the framebuffer is enabled in the default OpenRisc config
Add LPC32XX device

Add LPC32XX touch screen device and enable it by default in OpenRisc sim
machine