CEC: correct frameworks physicalAddress parsing

The HIDL interface defines physical address as a uint16_t, but Java
does not utilize unsigned types, so it represents this value as a
standard 32-bit signed integer type. However, it extends the MSB to
the full 32-bits instead of padding with zeroes, causing large
values to be read as negative, crashing the service when
HdmiPortInfo builder asserts >=0.

This also clarifies a related comment likely sourced from the same
incorrect assumption about how the parsing behaves.

Co-authored-by: Thomas Makin <halorocker89@gmail.com>
Co-authored-by: Aaron Kling <webgeek1234@gmail.com>

Change-Id: If101cf5a725315d75ea5315d4cf42c8d55fb7bec