Validation of large registers in suite 0

ValidatePciCapRegisterROAttribute() appears unreliable when the (size > MAX_SUPPORTED_REG_SIZE) branch is taken. The existing code reads a few bytes of the register into an uninitialised variable, without bit-shifting, and then compares against the complete expected value. Looks like it might be an unnoticed cut and paste mistake - the comparison succeeds if the expected value and the uninitialised variable both happen to be zero.