net: phy: realtek: Check the index value in led_hw_control_get

net: phy: realtek: Check the index value in led_hw_control_get

Just like rtl8211f_led_hw_is_supported() and
rtl8211f_led_hw_control_set(), the rtl8211f_led_hw_control_get() also
needs to check the index value, otherwise the caller is likely to get
an incorrect rules.

Fixes: 17784801d888 ("net: phy: realtek: Add support for PHY LEDs on RTL8211F")
Signed-off-by: Hui Wang <[email protected]>
Reviewed-by: Marek Vasut <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>