[lib][sysparam] add implementation of sysparams
[lib][sysparam] reimplement in terms of the block io layer
[lib][flash_ptable] add implementation of flash_ptable
[lib][ptable] rename flash_ptable to ptable

Convert to working on top of block devices instead of flash_nor.
[lib][bio] tweak api for subdevice publishing
[target][zybo] add sysparam and ptable support

Add some code in target init that sets up the spi flash ptable
and sysparam block.
[platform][zynq] quiet the flash driver