build/xilinx/vivado: merge migen change

litex/build/xilinx/vivado.py

@@ -214,14 +214,9 @@ class XilinxVivadoToolchain:
         )
 
     def build(self, platform, fragment, build_dir="build", build_name="top",
-            toolchain_path=None, source=True, run=True):
+            toolchain_path="/opt/Xilinx/Vivado", source=True, run=True, **kwargs):
         if toolchain_path is None:
-            if sys.platform == "win32":
-                toolchain_path = "C:\\Xilinx\\Vivado"
-            elif sys.platform == "cygwin":
-                toolchain_path = "/cygdrive/c/Xilinx/Vivado"
-            else:
-                toolchain_path = "/opt/Xilinx/Vivado"
+            toolchain_path = "/opt/Xilinx/Vivado"
         os.makedirs(build_dir, exist_ok=True)
         cwd = os.getcwd()
         os.chdir(build_dir)