leds: bcm63138: Add MODULE_DESCRIPTION()

Fix the 'make W=1" issue:

WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/leds/blink/leds-bcm63138.o
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Acked-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://lore.kernel.org/r/20240517-md-leds-bcm63138-v1-1-247b7302edb6@quicinc.comSigned-off-by: Lee Jones <lee@kernel.org>

drivers/leds/blink/leds-bcm63138.c

@@ -303,5 +303,6 @@ static struct platform_driver bcm63138_leds_driver = {
 module_platform_driver(bcm63138_leds_driver);
 
 MODULE_AUTHOR("Rafał Miłecki");
+MODULE_DESCRIPTION("Broadcom BCM63138 SoC LED driver");
 MODULE_LICENSE("GPL");
 MODULE_DEVICE_TABLE(of, bcm63138_leds_of_match_table);