stm32mp: Reserve OPTEE area in EFI memory map

stm32mp: Reserve OPTEE area in EFI memory map

Since commit 7b78d6438a2b3 ("efi_loader: Reserve unaccessible memory")
memory region above ram_top is tagged in EFI memory map as
EFI_BOOT_SERVICES_DATA.
In case of STM32MP1/STM32MP13 platforms, above ram_top, there is one
reserved-memory region tagged "no-map" dedicated to OP-TEE :
 _ addr=de000000 size=2000000 for stm32mp157x-dkx and stm32mp135f-dk
 _ addr=fe000000 size=2000000 for stm32mp157c-ev1

Before booting kernel, EFI memory map is first built, the OPTEE region is
tagged as EFI_BOOT_SERVICES_DATA and when reserving LMB, the tag LMB_NONE
is used.

Then after, the LMB are completed by boot_fdt_add_mem_rsv_regions()
which try to add again the same OPTEE region (addr=de000000 size=2000000
in case of stm32mp157x-dkx / stm32mp135f-dk or addr=fe000000 size=2000000
in case for stm2mp157c-ev1)
but now with LMB_NOMAP tag which produces the following error message :

 _ for stm32mp157x-dkx / stm32mp135f-dk :
  "ERROR: reserving fdt memory region failed (addr=de000000 size=2000000 flags=4)"

 _ for stm32mp157c-ev1 :
  "ERROR: reserving fdt memory region failed (addr=fe000000 size=2000000 flags=4)"

To avoid this, OPTEE area shouldn't be used by EFI, so we need to mark
it as reserved.

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