uio: uio_pruss: Fix potential NULL pointer dereference

In function pruss_probe we free gdev and try to use
it on the next line. I have moved the dereference to
above the kfree of gdev.

Signed-off-by: Emil Goode <emilgoode@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>