According to the the NVM Express spec Revision 1.1, for some commands
(like Get/Set Feature Command, Figure 89 & 90 of the spec), the Memory
Buffer maybe optional although the command opcode indicates there is a
data transfer between host & controller (Get/Set Feature Command, Figure
38 of the spec).
Hence, this commit refine the checks for the 'TransferLength' and
'TransferBuffer' field of the EFI_NVM_EXPRESS_PASS_THRU_COMMAND_PACKET
structure to address this issue.