[DM/MFD] Add QEMU EDU for PCI study

EDU Support DMA (lower 32 bits) and factorial, MSI-X, user can change device or driver
to study PCI.

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

components/drivers/mfd/SConscript

@@ -9,6 +9,9 @@ cwd = GetCurrentDir()
 CPPPATH = [cwd + '/../include']
 src = []
 
+if GetDepend(['RT_MFD_EDU']):
+    src += ['mfd-edu.c']
+
 if GetDepend(['RT_MFD_SYSCON']):
     src += ['mfd-syscon.c']