phy: cpcap-usb: Fix missing return statement

Commit 8ae904e3c236 ("phy: cpcap-usb: Add CPCAP PMIC USB support")
is missing return statement as noted by Colin Ian King
<colin.king@canonical.com>. If the optional pins are not configured,
we just want to return early and not attempt to configure the pins.

Fixes: 8ae904e3c236 ("phy: cpcap-usb: Add CPCAP PMIC USB support")
Reported-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>