fm10k/base: pack TLV overlay structures

This patch adds #pragma pack(push, 1) around some structures which are passed
via TLV messages. These structures must not be left unpacked as GCC and
other compilers are wont to do. Otherwise, we get invalid message
responses from the Switch Manager software since it sends 20 bytes and
we expect 24.

Solaris (and other OS's) are not C99 compliant, so they are not able
to use the C99 style #pragma pack() code. Wrap with C99 tag for easy
stripping.

Signed-off-by: Wang Xiao W <xiao.w.wang@intel.com>