ARM: socfpga: checking the wrong variable

This is a cut and paste bug.  We had intended to check "sysmgr".

Fixes: e5f8efa5 ("ARM: socfpga: fpga bridge driver support")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Moritz Fischer <moritz.fischer@ettus.com>
Acked-by: Alan Tull <atull@opensource.altera.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>