fm10k: pack TLV overlay structures

This patch adds the __attribute__((packed)) indicator to some structures
which are overlayed onto a TLV message. These structures must be packed
as small as possible in order to correctly align when copied into the
mailbox buffer. Without doing so, the receiving mailbox code incorrectly
parses the values and we get invalid message responses from the switch
manager software.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Krishneil Singh <Krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>