Add FLASH_TEST_PRBS debug mode (#4606)

Author: haslinghuis

src/js/debug.js

@@ -788,6 +788,13 @@ const DEBUG = {
             "debug[all]": "Chirp",
             "debug[0]": "Chirp sinarg",
         },
+        FLASH_TEST_PRBS: {
+            "debug[all]": "Flash Test PRBS",
+            "debug[0]": "State",
+            "debug[1]": "Flash Length",
+            "debug[6]": "FlashLength / Pagesize",
+            "debug[7]": "Errors",
+        },
     },
 
     enableFields: [
@@ -829,6 +836,7 @@ function update() {
         addArrayElementAfter(DEBUG.modes, "RANGEFINDER_QUALITY", "OPTICALFLOW");
         addArrayElement(DEBUG.modes, "AUTOPILOT_POSITION");
         addArrayElement(DEBUG.modes, "CHIRP");
+        addArrayElement(DEBUG.modes, "FLASH_TEST_PRBS");
         replaceArrayElement(DEBUG.modes, "DUAL_GYRO_RAW", "MULTI_GYRO_RAW");
         replaceArrayElement(DEBUG.modes, "DUAL_GYRO_DIFF", "MULTI_GYRO_DIFF");
         replaceArrayElement(DEBUG.modes, "DUAL_GYRO_SCALED", "MULTI_GYRO_SCALED");