common: fdt_fixup: manage 32 bits address in reserved memory

Reserved memory must be filled depending the architecture.
This patch automatically detect the address and size
length to adapt the address-cells and size-cells values.

Signed-off-by: Lionel Debieve <lionel.debieve@st.com>
Change-Id: I6e159a2f00805fd33a1f1ab76a8c4fd8c17d0c14
Reviewed-on: https://gerrit.st.com/c/mpu/oe/st/tf-a/+/186503


Reviewed-by: CITOOLS <smet-aci-reviews@lists.codex.cro.st.com>
Reviewed-by: CIBUILD <smet-aci-builds@lists.codex.cro.st.com>
Reviewed-by: Yann GAUTIER <yann.gautier@st.com>