xsysace: Remove SYSACE driver

Sysace IP is no longer used on Xilinx PowerPC 405/440 and Microblaze
systems. The driver is not regularly tested and very likely not working for
quite a long time that's why remove it.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>