kernel: Make kmod-usb-chipidea select kmod-phy-ath79-usb

kernel: Make kmod-usb-chipidea select kmod-phy-ath79-usb

The USB PHY on the ar9330 and similar SoCs needs the PHY driver. In
OpenWrt 23.05 it was compiled into the kernel. The kernel 6.6
configuration does not compile it in any more, make the
kmod-usb-chipidea driver select it to add it to the images.

Fixes: https://github.com/openwrt/openwrt/issues/17710
Fixes: 04bdf9b3323e ("ath79: disable ath79 USB phy drivers by default")
Link: https://github.com/openwrt/openwrt/pull/17720
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>