platform is modified in-place, no need to return

src/gateware/zc706.py

@@ -136,7 +136,6 @@ def prepare_zc706_platform(platform):
     ])
     platform.add_platform_command("create_clock -name clk_fpga_0 -period 8 [get_pins \"PS7/FCLKCLK[0]\"]")
     platform.add_platform_command("set_input_jitter clk_fpga_0 0.24")
-    return platform
 
 
 class ZC706(SoCCore):
@@ -145,7 +144,7 @@ class ZC706(SoCCore):
         self.rustc_cfg = dict()
 
         platform = zc706.Platform()
-        platform = prepare_zc706_platform(platform)
+        prepare_zc706_platform(platform)
 
         ident = self.__class__.__name__
         if self.acpki:
@@ -199,7 +198,7 @@ class _MasterBase(SoCCore):
         self.rustc_cfg = dict()
 
         platform = zc706.Platform()
-        platform = prepare_zc706_platform(platform)
+        prepare_zc706_platform(platform)
         ident = self.__class__.__name__
         if self.acpki:
             ident = "acpki_" + ident
@@ -337,7 +336,7 @@ class _SatelliteBase(SoCCore):
         self.rustc_cfg = dict()
 
         platform = zc706.Platform()
-        platform = prepare_zc706_platform(platform)
+        prepare_zc706_platform(platform)
         ident = self.__class__.__name__
         if self.acpki:
             ident = "acpki_" + ident