If devm_extcon_dev_allocate() fails, we should disable clk before return.

Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Fixes: 860d2686 ("usb: phy: tahvo: Use devm_extcon_dev_[allocate|register]() and replace deprecated API")
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>