hw/int/loongarch: Include missing 'system/memory.h' header

"system/memory.h" header is indirectly pulled by "hw/sysbus.h".
Include it explicitly to avoid when refactoring the latter:

  In file included from ../../hw/intc/loongson_ipi.c:9:
  In file included from /Users/philmd/source/qemu/include/hw/intc/loongson_ipi.h:12:
  include/hw/intc/loongson_ipi_common.h:37:18: error: field has incomplete type 'MemoryRegion' (aka 'struct MemoryRegion')
     37 |     MemoryRegion ipi_iocsr_mem;
        |                  ^

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Bibo Mao <maobibo@loongson.cn>
Message-Id: <20251024190416.8803-21-philmd@linaro.org>

include/hw/intc/loongarch_dintc.h

@@ -8,7 +8,7 @@
 #include "qom/object.h"
 #include "hw/sysbus.h"
 #include "hw/loongarch/virt.h"
-
+#include "system/memory.h"
 
 #define NR_VECTORS     256
 

include/hw/intc/loongarch_extioi_common.h

@@ -10,6 +10,7 @@
 #include "qom/object.h"
 #include "hw/sysbus.h"
 #include "hw/loongarch/virt.h"
+#include "system/memory.h"
 
 #define LS3A_INTC_IP                 8
 #define EXTIOI_IRQS                  (256)

include/hw/intc/loongarch_pch_msi.h

@@ -6,6 +6,7 @@
  */
 
 #include "hw/sysbus.h"
+#include "system/memory.h"
 
 #define TYPE_LOONGARCH_PCH_MSI "loongarch_pch_msi"
 OBJECT_DECLARE_SIMPLE_TYPE(LoongArchPCHMSI, LOONGARCH_PCH_MSI)

include/hw/intc/loongarch_pic_common.h

@@ -9,6 +9,7 @@
 
 #include "hw/loongarch/virt.h"
 #include "hw/sysbus.h"
+#include "system/memory.h"
 
 #define PCH_PIC_INT_ID                  0x00
 #define  PCH_PIC_INT_ID_VAL             0x7

include/hw/intc/loongson_ipi_common.h

@@ -11,6 +11,7 @@
 #include "qom/object.h"
 #include "hw/sysbus.h"
 #include "exec/memattrs.h"
+#include "system/memory.h"
 
 #define IPI_MBX_NUM           4