MIPS: Sibyte: remove unnecessary return variable

Fix the following coccicheck warning:

arch/mips/sibyte/bcm1480/setup.c:37:5-8: Unneeded variable: "ret".
Return "0" on line 67.
Signed-off-by: Guo Zhengkui <guozhengkui@vivo.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

arch/mips/sibyte/bcm1480/setup.c

@@ -34,8 +34,6 @@ static char *pass_str;
 
 static int __init setup_bcm1x80_bcm1x55(void)
 {
-	int ret = 0;
-
 	switch (soc_pass) {
 	case K_SYS_REVISION_BCM1480_S0:
 		periph_rev = 1;
@@ -64,7 +62,7 @@ static int __init setup_bcm1x80_bcm1x55(void)
 		break;
 	}
 
-	return ret;
+	return 0;
 }
 
 /* Setup code likely to be common to all SiByte platforms */