[Keyboard] Add the proton c as a controller for the redox (#16106)

Co-authored-by: Sergey Vlasov <sigprof@gmail.com>
Co-authored-by: xerootg <xerootg@github.com>

keyboards/redox/rev1/proton_c/mcuconf.h

@@ -0,0 +1,9 @@
+// Copyright 2022 xerootg
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include_next <mcuconf.h>
+
+#undef STM32_SERIAL_USE_USART1
+#define STM32_SERIAL_USE_USART1 TRUE