Configuration values for starting HSV and speed (qmk#7740)

* Define default HSV and speed for RGB matrix.

* Documentation for configuration values RGB_MATRIX_STARTUP_HUE, RGB_MATRIX_STARTUP_SAT and RGB_MATRIX_STARTUP_VAL.

* Document RGB_MATRIX_STARTUP_SPD.

* Preserve the ordering.

quantum/rgb_matrix.c

@@ -95,6 +95,23 @@ const point_t k_rgb_matrix_center = RGB_MATRIX_CENTER;
 #    endif
 #endif
 
+#if !defined(RGB_MATRIX_STARTUP_HUE)
+#    define RGB_MATRIX_STARTUP_HUE 0
+#endif
+
+#if !defined(RGB_MATRIX_STARTUP_SAT)
+#    define RGB_MATRIX_STARTUP_SAT UINT8_MAX
+#endif
+
+#if !defined(RGB_MATRIX_STARTUP_VAL)
+#    define RGB_MATRIX_STARTUP_VAL RGB_MATRIX_MAXIMUM_BRIGHTNESS
+#endif
+
+#if !defined(RGB_MATRIX_STARTUP_SPD)
+#    define RGB_MATRIX_STARTUP_SPD UINT8_MAX / 2
+#endif
+
+
 bool g_suspend_state = false;
 
 rgb_config_t rgb_matrix_config;
@@ -119,8 +136,8 @@ void eeconfig_update_rgb_matrix_default(void) {
     dprintf("eeconfig_update_rgb_matrix_default\n");
     rgb_matrix_config.enable = 1;
     rgb_matrix_config.mode   = RGB_MATRIX_STARTUP_MODE;
-    rgb_matrix_config.hsv    = (HSV){0, UINT8_MAX, RGB_MATRIX_MAXIMUM_BRIGHTNESS};
-    rgb_matrix_config.speed  = UINT8_MAX / 2;
+    rgb_matrix_config.hsv    = (HSV){RGB_MATRIX_STARTUP_HUE, RGB_MATRIX_STARTUP_SAT, RGB_MATRIX_STARTUP_VAL};
+    rgb_matrix_config.speed  = RGB_MATRIX_STARTUP_SPD;
     eeconfig_update_rgb_matrix();
 }