To ensure that child node is found, don't rely on child's node name
which can take different value, but on child's compatible name.

Fixes: f5c5936d ("usb: dwc3: st: Fix node's child name")
Cc: stable <stable@kernel.org>
Cc: Jerome Audu <jerome.audu@st.com>
Reported-by: Felipe Balbi <felipe@balbi.sh>
Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
Link: https://lore.kernel.org/r/20220930142018.890535-1-patrice.chotard@foss.st.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>