configs: imx93_var_som: Add fastboot support.

Enable the `fastboot` command.

Signed-off-by: Mathieu Othacehe <othacehe@gnu.org>

configs/imx93_var_som_defconfig

@@ -96,6 +96,12 @@ CONFIG_SPL_CLK_IMX93=y
 CONFIG_CLK_IMX93=y
 CONFIG_DFU_MMC=y
 CONFIG_DFU_RAM=y
+CONFIG_USB_FUNCTION_FASTBOOT=y
+CONFIG_FASTBOOT_BUF_ADDR=0x82800000
+CONFIG_FASTBOOT_BUF_SIZE=0x20000000
+CONFIG_FASTBOOT_FLASH=y
+CONFIG_FASTBOOT_UUU_SUPPORT=y
+CONFIG_FASTBOOT_FLASH_MMC_DEV=0
 CONFIG_GPIO_HOG=y
 CONFIG_IMX_RGPIO2P=y
 CONFIG_DM_PCA953X=y