usb: renesas_usbhs: fix error return code of usbhsf_pkt_handler()

When __usbhsf_pkt_get() returns NULL to pkt, no error return code of
usbhsf_pkt_handler() is assigned.
To fix this bug, ret is assigned with -EINVAL in this case.

Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Link: https://lore.kernel.org/r/20210307090030.22369-1-baijiaju1990@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>