clk: samsung: exynos542x: Enable clock rate propagation up to the EPLL

The CLK_SET_RATE_PARENT flag is added to clocks between the EPLL
and the audio subsystem clock controller so that the EPLL's output
frequency can be set indirectly with clk_set_rate() on a leaf clock.
That should be safe as EPLL is normally only used to generate clock
for the audio subsystem.
With this change we can avoid passing the EPLL clock to the ASoC
machine driver.

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>