rk3399: Add BOOTENV_SF command

Add missing BOOTENV_SF command in rk3399 config.

Fix it.

Fixes: f263b860 ("rk3399: Enable SF distro bootcmd")
Signed-off-by: NJagan Teki <jagan@amarulasolutions.com>
Reported-by: NSuniel Mahesh <sunil@amarulasolutions.com>
Tested-by: NSuniel Mahesh <sunil@amarulasolutions.com>
Reviewed-by: NKever Yang <kever.yang@rock-chips.com>

include/configs/rk3399_common.h

@@ -67,6 +67,7 @@
 	"partitions=" PARTS_DEFAULT \
 	ROCKCHIP_DEVICE_SETTINGS \
 	BOOTENV \
+	BOOTENV_SF \
 	"altbootcmd=" \
 		"setenv boot_syslinux_conf extlinux/extlinux-rollback.conf;" \
 		"run distro_bootcmd\0"