of: reserved-memory: Warn for missing static reserved memory regions

For child node of /reserved-memory, its property 'reg' may contain
multiple regions, but fdt_scan_reserved_mem_reg_nodes() only takes
into account the first region, and miss remaining regions.

But there are no simple approach to fix it, so give user warning
message when miss remaining regions.

Fixes: 8a6e02d0 ("of: reserved_mem: Restructure how the reserved memory regions are processed")
Cc: stable@vger.kernel.org
Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20250114-of_core_fix-v5-2-b8bafd00a86f@quicinc.com


Signed-off-by: Rob Herring (Arm) <robh@kernel.org>