device_mmio: use explicit unsigned literals for addresses

Add an explicit unsigned literal suffix (U) for addresses obtained from
devicetree, this is to work around a specific warning:

zephyrproject/zephyr/include/zephyr/arch/arm/cortex_a_r/timer.h:40:2:
warning: this decimal constant is unsigned only in ISO C90

When compling

west build -p -b qemu_cortex_a9 -T tests/lib/cpp/cxx/cpp.main.cpp98

Argueably all devicetree addresses and sizes should be unsigned but this
is enough to make CI pass, may look into changing the device.h macro as
a followup.

Signed-off-by: Fabio Baltieri <fabiobaltieri@google.com>

Author: fabiobaltieri

include/zephyr/sys/device_mmio.h

@@ -63,13 +63,13 @@ struct z_device_mmio_rom {
 
 #define Z_DEVICE_MMIO_ROM_INITIALIZER(node_id) \
 	{ \
-		.phys_addr = DT_REG_ADDR(node_id), \
+		.phys_addr = UINT32_C(DT_REG_ADDR(node_id)), \
 		.size = DT_REG_SIZE(node_id) \
 	}
 
 #define Z_DEVICE_MMIO_NAMED_ROM_INITIALIZER(name, node_id) \
 	{ \
-		.phys_addr = DT_REG_ADDR_BY_NAME(node_id, name), \
+		.phys_addr = UINT32_C(DT_REG_ADDR_BY_NAME(node_id, name)), \
 		.size = DT_REG_SIZE_BY_NAME(node_id, name) \
 	}