leds: trigger: Remove unused function led_trigger_rename_static()

[ Upstream commit c82a1662 ]

This function was added with a8df7b1a

 ("leds: add led_trigger_rename
function") 11 yrs ago, but it has no users. So remove it.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Link: https://lore.kernel.org/r/d90f30be-f661-4db7-b0b5-d09d07a78a68@gmail.com
Signed-off-by: Lee Jones <lee@kernel.org>
Stable-dep-of: ab477b766edd ("leds: triggers: Flush pending brightness before activating trigger")
Signed-off-by: Sasha Levin <sashal@kernel.org>