can: peak_usb: pcan_usb_fd_decode_status(): remove unnecessary test on the nullity of a pointer

Since alloc_can_err_skb() puts NULL in cf in the case when skb cannot
be allocated and can_change_state() handles the case when cf is NULL,
the test on the nullity of skb is now unnecessary.

Link: https://lore.kernel.org/all/20210929142111.55757-2-s.grosjean@peak-system.com


Signed-off-by: Stephane Grosjean <s.grosjean@peak-system.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>