led: Fix next Coverity scan error

led: Fix next Coverity scan error

The following was reported by Coverity scan:

*** CID 542488:  Control flow issues  (NO_EFFECT)
/drivers/led/led-uclass.c: 277 in led_get_function_name()
271                     return uc_plat->label;
272
273             /* Now try to detect function label name */
274             func = dev_read_string(dev, "function");
275             cp = dev_read_u32(dev, "color", &color);
276             // prevent coverity scan error CID 541279: (TAINTED_SCALAR)
>>>     CID 542488:  Control flow issues  (NO_EFFECT)
>>>     This less-than-zero comparison of an unsigned value is never true. "color < 0U".
277             if (color < LED_COLOR_ID_WHITE || color >= LED_COLOR_ID_MAX)
278                     cp = -EINVAL;
279

Fix it.

Addresses-Coverity-ID: 542488
Link: https://lists.denx.de/pipermail/u-boot/2025-February/581567.html
Signed-off-by: Heiko Schocher <hs@denx.de>
Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>