fm3 flash driver needs to know which chip variant is used.
This fixes "unknown fm3 variant: mb9bf500.cpu" error if the config is
used as is.
Change-Id: I500fcfb413f23ee246678cec5bd19d14139a28e2
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Reviewed-on: http://openocd.zylin.com/2160
Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>