configs: transformer: simplify boot command

Drop boot device sequence re-definition since now it is default.

Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
diff --git a/configs/transformer_t30_defconfig b/configs/transformer_t30_defconfig
index 11a552d..1ebdb31 100644
--- a/configs/transformer_t30_defconfig
+++ b/configs/transformer_t30_defconfig
@@ -20,7 +20,7 @@
 CONFIG_AUTOBOOT_KEYED_CTRLC=y
 CONFIG_OF_BOARD_SETUP=y
 CONFIG_OF_SYSTEM_SETUP=y
-CONFIG_BOOTCOMMAND="setenv boot_targets usb mmc1 mmc0; bootflow scan; poweroff"
+CONFIG_BOOTCOMMAND="bootflow scan; poweroff"
 CONFIG_SYS_PBSIZE=2084
 CONFIG_SPL_FOOTPRINT_LIMIT=y
 CONFIG_SPL_MAX_FOOTPRINT=0x8000