test: dm: Move the time test over to the ut command

Unify the command for running unit tests further by moving the "ut_time"
command over to "ut time".

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
diff --git a/configs/sandbox_defconfig b/configs/sandbox_defconfig
index e69f147..7b5ef2b 100644
--- a/configs/sandbox_defconfig
+++ b/configs/sandbox_defconfig
@@ -37,5 +37,5 @@
 CONFIG_USB_STORAGE=y
 CONFIG_DM_RTC=y
 CONFIG_ERRNO_STR=y
-CONFIG_CMD_UT_TIME=y
+CONFIG_UT_TIME=y
 CONFIG_UT_DM=y