spiflash: add read-only variable data width spi flash
lx9crg: add crg for lx9 microboard
make.py, top.py: tweaks for lx9 microboard

sdram is 64M on lx9 microboard

lx9 only needs 320k config mem in flash
tdcdtc: preliminary version of serdes based TDC+DTC wishbone peripheral
memtest: shrink memtest space to 32M for lx9 microboard