fix: remove duplicate autotrim macro definitions from servos.c

Commit 58dc107 re-added SERVO_AUTOTRIM_FILTER_CUTOFF and related
constants to servos.c as local #defines, but they were already moved
to servos.h by a prior refactor (dcc404e). The duplicate caused a
build error: the .c definition used integer 1 while the header has
1.0f, triggering -Werror,-Wmacro-redefined on all targets.

Remove the redundant block from servos.c and add the one genuinely
new constant (SERVO_AUTOTRIM_ITERM_RATE_LIMIT) to servos.h alongside
the existing autotrim constants.

Author: sensei-hacker

src/main/flight/servos.c

@@ -607,13 +607,6 @@ void processServoAutotrimMode(void)
     }
 }
 
-#define SERVO_AUTOTRIM_FILTER_CUTOFF    1       // LPF cutoff frequency
-#define SERVO_AUTOTRIM_CENTER_MIN       1300
-#define SERVO_AUTOTRIM_CENTER_MAX       1700
-#define SERVO_AUTOTRIM_UPDATE_SIZE      5
-#define SERVO_AUTOTRIM_ATTITUDE_LIMIT   50       // 5 degrees
-#define SERVO_AUTOTRIM_ITERM_RATE_LIMIT 30  // ~90th percentile during stable cruise (blackbox-derived)
-
 void processContinuousServoAutotrim(const float dT)
 {
     static timeMs_t lastUpdateTimeMs;

src/main/flight/servos.h

@@ -166,6 +166,7 @@ PG_DECLARE_ARRAY(servoParam_t, MAX_SUPPORTED_SERVOS, servoParams);
 #define SERVO_AUTOTRIM_CENTER_MAX       1700
 #define SERVO_AUTOTRIM_UPDATE_SIZE      5
 #define SERVO_AUTOTRIM_ATTITUDE_LIMIT   50       // 5 degrees
+#define SERVO_AUTOTRIM_ITERM_RATE_LIMIT 30       // ~90th percentile during stable cruise (blackbox-derived)
 
 typedef struct servoConfig_s {
     // PWM values, in milliseconds, common range is 1000-2000 (1ms to 2ms)