leds: class: Don't expose color sysfs entry

The commit c7d80059 ("leds: class: Store the color index in struct
led_classdev") introduced a new sysfs entry "color" that is commonly
created for the led classdev.  Unfortunately, this conflicts with the
"color" sysfs entry of already existing drivers such as Logitech HID
or System76 ACPI drivers.  The driver probe fails due to the conflict,
hence it leads to a severe regression with the missing keyboard, for
example.

This patch reverts partially the change in the commit above for
removing the led class color sysfs entries again for addressing the
regressions.  The newly introduced led_classdev.color field is kept as
it's already used by other driver.

Fixes: c7d80059

 ("leds: class: Store the color index in struct led_classdev")
Reported-by: Johannes Penßel <johannes.penssel@gmail.com>
Closes: https://lore.kernel.org/r/b5646db3-acff-45aa-baef-df3f660486fb@gmail.com
Link: https://bugzilla.kernel.org/show_bug.cgi?id=218045
Link: https://bugzilla.kernel...