The check for < 0 is impossible now that
of_clk_get_parent_count() returns an unsigned int. Simplify the
code and update the types.
Acked-by: NFelipe Balbi <balbi@kernel.org>
Cc: <linux-usb@vger.kernel.org>
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>