configs: stm32mp13: activate command stm32prog

Activate the command stm32prog with CONFIG_CMD_STM32MPROG.
The CONFIG_SET_DFU_ALT_INFO is also activated to support
the required weak functions for the DFU virtual backen defined in
board/st/common/stm32mp_dfu.c.

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>