configs: stm32mp1: enable the fastboot oem command partconf

Enable the fastboot oem command partconf, used to select the correct
eMMC boot partition, with same format than 'mmc partconf'
with parameter: boot_ack boot_partition
On stm32mp1 family:
- boot_ack = 1 (Boot Acknowledge is needed by ROM code)
- boot_partition = 1 or 2 (Boot partition 1 / 2 enabled for boot)

So on EV1 board the expected commands to select boot partition 1 or 2
$> fastboot oem partconf:1 1
$> fastboot oem partconf:1 2

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@st.com>
diff --git a/configs/stm32mp15_basic_defconfig b/configs/stm32mp15_basic_defconfig
index 9c207d0..836bcee 100644
--- a/configs/stm32mp15_basic_defconfig
+++ b/configs/stm32mp15_basic_defconfig
@@ -85,6 +85,7 @@
 CONFIG_FASTBOOT_MMC_USER_SUPPORT=y
 CONFIG_FASTBOOT_MMC_USER_NAME="mmc1"
 CONFIG_FASTBOOT_CMD_OEM_FORMAT=y
+CONFIG_FASTBOOT_CMD_OEM_PARTCONF=y
 CONFIG_GPIO_HOG=y
 CONFIG_DM_HWSPINLOCK=y
 CONFIG_HWSPINLOCK_STM32=y