armv8: fsl_lsch2: Add SerDes 2 support

New SoC LS1046A belongs to Freescale Chassis Generation 2 and
has two SerDes so we need to add this support in fsl_lsch2.
The SoC related SerDes 2 support will be added in SoC patch.

Signed-off-by: Gong Qianyu <Qianyu.Gong@nxp.com>
Reviewed-by: York Sun <york.sun@nxp.com>
diff --git a/arch/arm/include/asm/arch-fsl-layerscape/fsl_serdes.h b/arch/arm/include/asm/arch-fsl-layerscape/fsl_serdes.h
index 487cba8..1f33404 100644
--- a/arch/arm/include/asm/arch-fsl-layerscape/fsl_serdes.h
+++ b/arch/arm/include/asm/arch-fsl-layerscape/fsl_serdes.h
@@ -140,6 +140,7 @@
 
 enum srds {
 	FSL_SRDS_1  = 0,
+	FSL_SRDS_2  = 1,
 };
 
 #endif