Handle in boot_fdt_reserve_region
any return value > 0 of lmb_reserve() function;
it occurs when coalesced region are found:
adjacent reserved region are merged.
This patch avoid the error trace:
ERROR: reserving fdt memory region failed..
when reserved region are merged (return value = 1).
Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>