Fix I2S::read/write(buffer, cnt) to return bytes (#3086)

::write and ::read should always return the number of bytes processed, but
we were only returing the ARB result which is *words* written.  Adjust the
outputs to be correct.

Author: earlephilhower

libraries/I2S/src/I2S.cpp

@@ -568,15 +568,15 @@ size_t I2S::read(uint8_t *buffer, size_t size) {
     if (size & 0x3 || !_running || !_isInput) {
         return 0;
     }
-    return _arbInput->read((uint32_t *)buffer, size / sizeof(uint32_t), false);
+    return 4 * _arbInput->read((uint32_t *)buffer, size / sizeof(uint32_t), false);
 }
 
 size_t I2S::write(const uint8_t *buffer, size_t size) {
     // We can only write 32-bit chunks here
     if (size & 0x3 || !_running || !_isOutput) {
         return 0;
     }
-    return _arbOutput->write((const uint32_t *)buffer, size / sizeof(uint32_t), false);
+    return 4 * _arbOutput->write((const uint32_t *)buffer, size / sizeof(uint32_t), false);
 }
 
 int I2S::availableForWrite() {