flash/nor: Add Infineon XMC1000 flash driver

The XMC1000 family uses a very different flash interface from XMC4000.

Tested on XMC 2Go and XMC1100 Boot Kit.

Change-Id: I3edaed420ef1c0fb89fdf221022c8b04163d41b3
Signed-off-by: Andreas Färber <afaerber@suse.de>
Reviewed-on: http://openocd.zylin.com/3418


Reviewed-by: Freddie Chopin <freddie.chopin@gmail.com>
Tested-by: jenkins