Fix mistyped output report message for Steam Controller

This caused hiccups in BlueZ BT driver for Linux

(cherry picked from commit bb3c61390ab4ba4fba6b542451a6dc26566eb5cf)

src/joystick/hidapi/steam/controller_structs.h

@@ -179,9 +179,8 @@ typedef struct
     uint16_t on_us;
     uint16_t off_us;
     uint16_t repeat_count;
-    uint16_t gain_db; 
 } MsgHapticPulse;
-#define HID_HAPTIC_PULSE_OUTPUT_REPORT_BYTES 10
+#define HID_HAPTIC_PULSE_OUTPUT_REPORT_BYTES 8
 
 typedef struct
 {