sb/amd/cimx/sb800/fan.c: Remove unuseful 'return' in void function

Change-Id: I458ff53bb9ae3a6c1003ee857b61fb350152cc86
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/61485
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Martin Roth <martinroth@google.com>

src/southbridge/amd/cimx/sb800/fan.c

@@ -280,6 +280,4 @@ if (sb_chip->imc_tempin3_enabled) {
 	sb_config.StdHeader.Func = SB_EC_FANCONTROL;
 
 	AmdSbDispatcher(&sb_config);
-
-	return;
 }