acm: move acm_[ep dest] definitions to acm_shared.h

Moving above data structures definitions was done
for later support of acm_ssa mode.

Signed-off-by: Ilya Nelkenbaum <ilyan@mellanox.com>
Signed-off-by: Hal Rosenstock <hal@mellanox.com>
common.h: add mutex lock to ssa_port

The lock only initialized and destroyed.
TBD: proper port locking for ssa methods.

The patch is a precursor patch for moving ACM
cache to SSA side.

Signed-off-by: Ilya Nelkenbaum <ilyan@mellanox.com>
Signed-off-by: Hal Rosenstock <hal@mellanox.com>