xhci: host: potential NULL dereference in xhci_generic_plat_probe()

It's possible to exit the loop with "sysdev" set to NULL.  In that
case we should use "&pdev->dev".

Fixes: ec5499d3 ("xhci: split out rcar/rz support from xhci-plat.c")
Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/Y+T4kTcJwRwxNHJq@kili


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