net: phy: add support for PHY LEDs polarity modes

Add support for PHY LEDs polarity modes. Some PHY require LED to be set
to active low to be turned ON. Adds support for this by declaring
active-low property in DT.

PHY driver needs to declare .led_polarity_set() to configure LED
polarity modes. Function will pass the index with the LED index and a
bitmap with all the required modes to set.

Current supported modes are:
- active-low with the flag PHY_LED_ACTIVE_LOW. LED is set to active-low
  to turn it ON.
- inactive-high-impedance with the flag PHY_LED_INACTIVE_HIGH_IMPEDANCE.
  LED is set to high impedance to turn it OFF.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20240125203702.4552-4-ansuelsmth@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>