Added Cortex-M0plus "ZeroGecko" Family to flash driver. Tested on EFM32ZG222F32. Change-Id: I1660b34ef6ee04837e97581504fff0faf84d1c6d Signed-off-by: Nemui Trinomius <nemuisan_kawausogasuki@live.jp> Reviewed-on: http://openocd.zylin.com/1994 Tested-by: jenkins Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>