Revert "board: st: stm32mp1: Clean env_get_location()"

This reverts commit d37641c.

Restore support for environment storage in EXT4 filesystem on eMMC boot.
The previous cleanup incorrectly removed this fallback option which is
needed for boards that store their environment in an EXT4 partition.

This configuration is OS-specific rather than board-dependent and should
remain as it is configurable via menuconfig. Even if it is not described
in ST defconfigs people may have enabled it in their defconfig.

Signed-off-by: Kory Maincent <[email protected]>
Reviewed-by: Patrice Chotard <[email protected]>

Author: kmaincent

board/st/stm32mp1/stm32mp1.c

@@ -751,6 +751,8 @@ enum env_location env_get_location(enum env_operation op, int prio)
 	case BOOT_FLASH_EMMC:
 		if (CONFIG_IS_ENABLED(ENV_IS_IN_MMC))
 			return ENVL_MMC;
+		else if (CONFIG_IS_ENABLED(ENV_IS_IN_EXT4))
+			return ENVL_EXT4;
 		else
 			return ENVL_NOWHERE;