Elon Musk laughed at BYD in 2011. Warren Buffett's Berkshire Hathaway has made nearly 40 times its money on the Chinese EV stock. Musk dismissed BYD as a Tesla rival, but Berkshire's $232 million bet on the automaker in 2008 has ballooned in value to over $9 billion today. – Elon Musk dismissed BYD as a Tesla rival in 2011, ridiculing the design and quality of its vehicles. – Warren Buffett's Berkshire Hathaway has made a nearly 40-fold gain on the Chinese automaker's stock. – Berkshire spent $232 million in 2008 for a stake valued at more than $9 billion…