Kconfig: cmd: Make networking command dependent on NET

Enable networking command only when NET is enabled.
And remove selecting NET for CMD_NET

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/vct_platinumavc_defconfig b/configs/vct_platinumavc_defconfig
index 32624c3..57b3077 100644
--- a/configs/vct_platinumavc_defconfig
+++ b/configs/vct_platinumavc_defconfig
@@ -16,3 +16,4 @@
 CONFIG_ENV_IS_IN_FLASH=y
 CONFIG_MTD_NOR_FLASH=y
 CONFIG_SYS_NS16550=y
+# CONFIG_REGEX is not set