phy: freescale: fsl-samsung-hdmi: Refactor finding PHY settings

phy: freescale: fsl-samsung-hdmi: Refactor finding PHY settings

There are two functions, round_rate and set_rate that duplicate
a lot of the same work, so simplify the code by creating a helper
function that will identify the phy settings for a desired clock
rate and return the structure with the corresponding settings.
>From this structure, the round_rate and set_rate can both get what
they need to achieve the clock setting closest to the desired rate
as possible while minimizing the duplicated code.

Also rename phy_clk_set_rate to fsl_samsung_hdmi_phy_clk_set_rate.

Suggested-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Signed-off-by: Adam Ford <aford173@gmail.com>
Link: https://lore.kernel.org/r/20250504204043.418924-2-aford173@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>