[DM/FEATURE] Support LED

Provides general LED control API and drivers.
It can work on PWM, GPIO and Syscon...

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

components/drivers/led/SConscript

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