arm64: dts: qcom: lemans: Fix dts inclusion for IoT boards and update memory map

arm64: dts: qcom: lemans: Fix dts inclusion for IoT boards and update memory map

IoT boards currently inherit the automotive memory map, which is not
suitable for their configuration. This leads to incorrect memory layout
and inclusion of unnecessary carveouts.

Use lemans.dtsi as the base for IoT boards to apply the correct memory
map. Include additional DTSI files as needed to complete the board
configuration.

Update 'model' string to represent these boards as 'lemans'.

Signed-off-by: Wasim Nazir <wasim.nazir@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250803110113.401927-7-wasim.nazir@oss.qualcomm.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>