Logger: replace RC keyword by 'manual control'

Signed-off-by: Silvan Fuhrer <silvan@auterion.com>

src/modules/logger/params.c

@@ -59,7 +59,7 @@ PARAM_DEFINE_INT32(SDLOG_UTC_OFFSET, 0);
  * @value 0 when armed until disarm (default)
  * @value 1 from boot until disarm
  * @value 2 from boot until shutdown
- * @value 3 depending on AUX1 RC channel
+ * @value 3 depending on manual control switch AUX1
  * @value 4 from 1st armed until shutdown
  *
  * @reboot_required true