[RFC 0/5] MIPS: add XBurst processor family support

[Antony Pavlov]

This patch series introduce XBurst processor family support to barebox.

XBurst is an CPU family developed by Ingenic Semiconductor
to address the requirements of mobile devices. XBurst processors
are used in mobile gaming consoles (e.g. notable Dingoo A320),
e-books, mp3-players and so on.

The patches have preliminary status. Please, review it!

[RFC 1/5] MIPS: add common header file for DEBUG_LL via NS16550
[RFC 2/5] MIPS: add XBurst processor family support
[RFC 3/5] MISP: XBurst: add JZ4755 CPU support
[RFC 4/5] MIPS: XBurst: add Ritmix RZX-50 board support
[RFC 5/5] MIPS: add defconfig for Ritmix RZX-50 board