[dm][serial] make DM Kconfig import

Signed-off-by: GuEe-GUI <2991707448@qq.com>

components/drivers/serial/Kconfig

@@ -1,5 +1,5 @@
 menuconfig RT_USING_SERIAL
-    bool "USING Serial device drivers"
+    bool "Using Serial device drivers"
     select RT_USING_DEVICE_IPC
     select RT_USING_DEVICE
     default y
@@ -36,3 +36,7 @@ menuconfig RT_USING_SERIAL
             bool "Using serial bypass"
             default n
         endif
+
+if RT_USING_DM && RT_USING_SERIAL
+    rsource "device/Kconfig"
+endif

components/drivers/serial/device/Kconfig

@@ -0,0 +1 @@
+osource "$(SOC_DM_SERIAL_DIR)/Kconfig"

components/drivers/serial/device/SConscript

@@ -0,0 +1,19 @@
+from building import *
+
+objs = []
+
+cwd = GetCurrentDir()
+list = os.listdir(cwd)
+CPPPATH = [cwd + '/../../include']
+
+src = []
+
+group = DefineGroup('DeviceDrivers', src, depend = [''], CPPPATH = CPPPATH)
+
+for d in list:
+    path = os.path.join(cwd, d)
+    if os.path.isfile(os.path.join(path, 'SConscript')):
+        objs = objs + SConscript(os.path.join(d, 'SConscript'))
+objs = objs + group
+
+Return('objs')