arm: mvebu: turris_omnia: Enable ENV support in SPL

Allow to read ENV variables also in SPL on Turris Omnia.

Signed-off-by: Pali Rohár <pali@kernel.org>
diff --git a/configs/turris_omnia_defconfig b/configs/turris_omnia_defconfig
index ad56d38..f310deb 100644
--- a/configs/turris_omnia_defconfig
+++ b/configs/turris_omnia_defconfig
@@ -37,6 +37,7 @@
 CONFIG_DISPLAY_BOARDINFO_LATE=y
 CONFIG_MISC_INIT_R=y
 CONFIG_SPL_BOARD_INIT=y
+CONFIG_SPL_ENV_SUPPORT=y
 CONFIG_SPL_I2C=y
 CONFIG_CMD_MEMTEST=y
 CONFIG_SYS_ALT_MEMTEST=y