arm: dts: stm32: Add partitions in flash0 and nand node for stm32mp15xx-ev1

arm: dts: stm32: Add partitions in flash0 and nand node for stm32mp15xx-ev1

Add partitions subnode in flash0 and nand nodes for all stm32mp157xx-ev1
boards. Update only the file stm32mp157c-ev1-*u-boot.dtsi, included by
other files  stm32mp15*-ev1-*-u-boot.dtsi.

For SCMI variant of device tree used with stm32mp15_defconfig
add partitions needed by TF-A firmware update:
- metadata to save the TF-A information: 2 copy
- fip-a / fip-b: two FIP slots, used for system A/B (seamless) update
- the previous "fsbl" partition with 2 copy of TFA is replaced
  by 2 partitions (only one copy in each MTD partition) to simplify
  the update: no need to managed this copy on update, need to update the
  two partition (skip bad block for NAND)
The offset for ENV partition are also updated in stm32mp15_defconfig

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