MSCC: add support for Luton SoCs

As the Ocelots SoCs, this family of SoCs are found in the Microsemi
Switches solution.

Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
diff --git a/arch/mips/mach-mscc/dram.c b/arch/mips/mach-mscc/dram.c
index 5acee6f..309007c 100644
--- a/arch/mips/mach-mscc/dram.c
+++ b/arch/mips/mach-mscc/dram.c
@@ -19,9 +19,11 @@
 
 	ret = hal_vcoreiii_train_bytelane(0);
 
+#ifdef CONFIG_SOC_OCELOT
 	if (ret)
 		return ret;
 	ret = hal_vcoreiii_train_bytelane(1);
+#endif
 
 	return ret;
 }