cfg:xilinx&zynq: re-arrange a few configs (serial and debug) and add some
new fragments.
iommu - IO capable memory management.
uio-irq - IRQ passthrough to UIO
uart-lite
cma - Contiguous memory allocation

Signed-off-by: Sipke Vriend <sipke.vriend@xilinx.com>
cfg:microblaze - add Microblaze specific config fragments.

debug.scc - include xilinx chosen debug options
microblaze-arch.scc and .cfg - selects microblaze as architecture and
enables/(disables) disables some must (not) have configs.

Signed-off-by: Sipke Vriend <sipke.vriend@xilinx.com>