usb: spear-ehci/ohci: Do clk_get using dev-id

We used to get clk using con-id, but now we have device struct available for
these devices as they are probed using DT. And so must get clk using dev-id.

Signed-off-by: Amardeep Rai <amardeep.rai-ext@st.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>