Delete useless files

Remove tags

Remove include/linux/mtd_bak
Remove ubifs and yaffs2
Leave jz4750d platform only, remove other jz47xx boards
Add separate Dingoo a380 board

Fix board name

Separate key driver for A380

A380: a380_gpio_keys: remove using poweroff_irq_flag

Separate Dingoo a380 video driver

Seperate udc_hotplug, gsensor, radio-rda5807p and elan drivers
Add separate Ritmix rzx50 board

RZX50: Fix definitions for rzx50_gpio_keys.c and jz4750_lcd_rzx50.h

RZX50: Fix board name during jz_board_setup()