Revert "configs: stm32mp1: only support SD card after NOR in bootcmd_stm32mp"

This reverts commit d5d726d3,
which breaks boards which ship with multiple SD/eMMC sockets.

This stm32mp1.h config is not used only by the ST reference
boards, but all the other STM32MP1 based boards in U-Boot, so
changes to this stm32mp1.h cannot break the other boards.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Patrice Chotard <patrice.chotard@foss.st.com>
Cc: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>