sysclk: code cleanup and fan speed

also fix incompatibility with nx fancontrol

Source/sys-clk/common/include/pwm.h

@@ -0,0 +1,22 @@
+#pragma once
+
+#include <switch.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct {
+    Service s;
+} PwmChannelSession;
+
+Result pwmInitialize(void);
+void pwmExit(void);
+Service* pwmGetServiceSession(void);
+Result pwmOpenSession2(PwmChannelSession *out, u32 device_code);
+Result pwmChannelSessionGetDutyCycle(PwmChannelSession *c, double* out);
+void pwmChannelSessionClose(PwmChannelSession *c);
+
+#ifdef __cplusplus
+} // extern "C"
+#endif