can: pcan_usb: fix wrong memcpy() bytes length

commit 3c322a56b01695df15c70bfdc2d02e0ccd80654e upstream.

Fix possibly wrong memcpy() bytes length since some CAN records received from
PCAN-USB could define a DLC field in range [9..15].
In that case, the real DLC value MUST be used to move forward the record pointer
but, only 8 bytes max. MUST be copied into the data field of the struct
can_frame object of the skb given to the network core.

Signed-off-by: Stephane Grosjean <s.grosjean@peak-system.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>