HID: sony: remove redundant check for -ve err

err is being checked for failure each time it is being updated
so this err check is totally redundant and can be removed

Detected with CoverityScan, CID#1420665 ("Logically dead code")

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>