The missing driver is the JDBC one and you have to add it to the SparkSQL configuration. You can do it through your Properties object with this line:
prop.setProperty("driver", "com.mysql.jdbc.Driver")
Or, in your case, the complete statement should be as below,
val df = spark.read.format("jdbc").option("url", "jdbc:mysql://sqoopdb.edu.cloudlab.com/z_dinesh").option("driver", "com.mysql.jdbc.Driver").option("dbtable", "t").option("user", "labuser").option("password", "edureka").load()
Also, make sure that the MySQL JDBC connection jar is added to the program.