usb: renesas_usbhs: fixup inconsistent return from usbhs_pkt_push()

usbhs_pkt_push() had inconsistent return under spin lock.
This patch fix it up.
Special thanks to Dan

Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>