[dm][rpmsg] support Remote Processor Messaging (RPMSG)

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

components/drivers/rpmsg/SConscript

@@ -0,0 +1,15 @@
+from building import *
+
+group = []
+
+if not GetDepend(['RT_USING_RPMSG']):
+    Return('group')
+
+cwd = GetCurrentDir()
+CPPPATH = [cwd + '/../include']
+
+src = ['rpmsg.c', 'rpmsg_char.c', 'rpmsg_ns.c']
+
+group = DefineGroup('DeviceDrivers', src, depend = [''], CPPPATH = CPPPATH)
+
+Return('group')