net: dsa: gswip: Fix copy-paste error in gswip_gphy_fw_probe()

The return value from of_reset_control_array_get_exclusive() is not
checked correctly. The test is done against a wrong variable. This
patch fix it.

Fixes: 14fceff4 ("net: dsa: Add Lantiq / Intel DSA driver for vrx200")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Acked-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: David S. Miller <davem@davemloft.net>