AP_BoardConfig: updated BRD_PWM_COUNT docs

This reflects the use of this parameter under ChibiOS

libraries/AP_BoardConfig/AP_BoardConfig.cpp

@@ -107,8 +107,8 @@ AP_BoardConfig *AP_BoardConfig::instance;
 const AP_Param::GroupInfo AP_BoardConfig::var_info[] = {
     // @Param: PWM_COUNT
     // @DisplayName: Auxiliary pin config
-    // @Description: Control assigning of FMU pins to PWM output, timer capture and GPIO. All unassigned pins can be used for GPIO
-    // @Values: 0:No PWMs,2:Two PWMs,4:Four PWMs,6:Six PWMs,7:Three PWMs and One Capture
+    // @Description: Controls number of FMU outputs which are setup for PWM. All unassigned pins can be used for GPIO
+    // @Values: 0:No PWMs,1:One PWMs,2:Two PWMs,3:Three PWMs,4:Four PWMs,5:Five PWMs,6:Six PWMs,7:Seven PWMs,8:Eight PWMs
     // @RebootRequired: True
     // @User: Advanced
     AP_GROUPINFO("PWM_COUNT",    0, AP_BoardConfig, pwm_count, BOARD_PWM_COUNT_DEFAULT),