phy: freescale: imx8m-pcie: cleanup reset logic

phy: freescale: imx8m-pcie: cleanup reset logic

Remove the switch statement and base perst release on whether it is
found in the device tree. The probe function fails without the reset
property, making it mandatory. Therefore, always release reset
independent of the variant.

This does not change the behavior of the driver but reduces driver
complexity and allows for easier future modifications.

Signed-off-by: Stefan Eichenberger <stefan.eichenberger@toradex.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20250305144355.20364-2-eichest@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>