Documentation: devres: add missing PHY helpers

Add devm_usb_get_phy_by_phandle() to devres.rst. It's introduced
by commit 5d3c28b5 ("usb: otg: add device tree support to otg
library").

Add devm_usb_get_phy_by_node() to devres.rst. It's introduced by
commit e842b84c ("usb: phy: Add interface to get phy give of
device_node.")

Fixes: 5d3c28b5 ("usb: otg: add device tree support to otg library")
Fixes: e842b84c

 ("usb: phy: Add interface to get phy give of device_node.")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20221103020625.1003759-1-yangyingliang@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>