fpga: dfl: fme: remove set but not used variable 'priv'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/fpga/dfl-fme-pr.c: In function 'pr_mgmt_uinit':
drivers/fpga/dfl-fme-pr.c:447:18: warning:
 variable 'priv' set but not used [-Wunused-but-set-variable]

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Acked-by: Moritz Fischer <mdf@kernel.org>
Acked-by: Wu Hao <hao.wu@intel.com>
Acked-by: Alan Tull <atull@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>