board: gateworks: venice: add eraseenv command

Add eraseenv command and remove the unnecessary env command.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Reviewed-by: Fabio Estevam <festevam@denx.de>
diff --git a/configs/imx8mn_venice_defconfig b/configs/imx8mn_venice_defconfig
index dc0bb01..8a0b8c2 100644
--- a/configs/imx8mn_venice_defconfig
+++ b/configs/imx8mn_venice_defconfig
@@ -54,6 +54,7 @@
 CONFIG_SYS_BOOTM_LEN=0x10000000
 # CONFIG_CMD_EXPORTENV is not set
 # CONFIG_CMD_IMPORTENV is not set
+CONFIG_CMD_ERASEENV=y
 CONFIG_CRC32_VERIFY=y
 CONFIG_CMD_MD5SUM=y
 CONFIG_MD5SUM_VERIFY=y