phy: qcom-qmp: Expose provided clocks to DT

Register a simple clock provider for the PHY pipe clock sources so that
device tree users can point at these clocks via phandles to the lane
nodes.

Signed-off-by: Evan Green <evgreen@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Tested-by: Vivek Gautam <vivek.gautam@codeaurora.org>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>