net: keystone_serdes: add keystone K2L SoC support

Keystone2 Lamar SoC uses the same keystone SerDes driver.
All Keystone2 EVM boards currently use SerDes driver, so move
CONFIG_TI_KEYSTONE_SERDES to common configuration file.

Acked-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>
diff --git a/drivers/net/keystone_net.c b/drivers/net/keystone_net.c
index c8681d0..83eeeda 100644
--- a/drivers/net/keystone_net.c
+++ b/drivers/net/keystone_net.c
@@ -582,7 +582,7 @@
 			&ks2_serdes_sgmii_156p25mhz,
 			CONFIG_KSNET_SERDES_LANES_PER_SGMII);
 
-#ifdef CONFIG_SOC_K2E
+#if defined(CONFIG_SOC_K2E) || defined(CONFIG_SOC_K2L)
 	ks2_serdes_init(CONFIG_KSNET_SERDES_SGMII2_BASE,
 			&ks2_serdes_sgmii_156p25mhz,
 			CONFIG_KSNET_SERDES_LANES_PER_SGMII);