net: Rename SPL_NET_SUPPORT to SPL_NET

Rename this option so that CONFIG_IS_ENABLED can be used with it.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/am335x_sl50_defconfig b/configs/am335x_sl50_defconfig
index 2a70ffc..aa1e196 100644
--- a/configs/am335x_sl50_defconfig
+++ b/configs/am335x_sl50_defconfig
@@ -29,7 +29,7 @@
 CONFIG_SPL_NAND_DRIVERS=y
 CONFIG_SPL_NAND_ECC=y
 CONFIG_SPL_NAND_BASE=y
-CONFIG_SPL_NET_SUPPORT=y
+CONFIG_SPL_NET=y
 CONFIG_SPL_NET_VCI_STRING="AM335x U-Boot SPL"
 CONFIG_SPL_OS_BOOT=y
 CONFIG_SPL_POWER=y