common/Makefile: Add new symbol CONFIG_SPL_ENV_SUPPORT for environment in SPL

There will need the environment in SPL for reasons other than network
support (in particular, hwconfig contains info for how to set up DDR).

Add a new symbol CONFIG_SPL_ENV_SUPPORT to replace CONFIG_SPL_NET_SUPPORT
for environment in common/Makefile.

Signed-off-by: Ying Zhang <b40530@freescale.com>
Reviewed-by: Tom Rini <trini@ti.com>
Signed-off-by: Andy Fleming <afleming@freescale.com>
diff --git a/include/configs/pcm051.h b/include/configs/pcm051.h
index 2ecd105..9b16c47 100644
--- a/include/configs/pcm051.h
+++ b/include/configs/pcm051.h
@@ -231,6 +231,7 @@
 #define CONFIG_SPL_GPIO_SUPPORT
 #define CONFIG_SPL_YMODEM_SUPPORT
 #define CONFIG_SPL_NET_SUPPORT
+#define CONFIG_SPL_ENV_SUPPORT
 #define CONFIG_SPL_NET_VCI_STRING	"pcm051 U-Boot SPL"
 #define CONFIG_SPL_ETH_SUPPORT
 #define CONFIG_SPL_SPI_SUPPORT