mlx4_core: mtt modifications for SRIOV

MTTs are resources which are allocated and tracked by the PF driver.
In multifunction mode, the allocation and icm mapping is done in
the resource tracker (later patch in this sequence).

To accomplish this, we have "work" functions whose names start with
"__", and "request" functions (same name, no __). If we are operating
in multifunction mode, the request function actually results in
comm-channel commands being sent (ALLOC_RES or FREE_RES).
The PF-driver comm-channel handler will ultimately invoke the
"work" (__) function and return the result.

If we are not in multifunction mode, the "work" handler is invoked
immediately.

Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: David S. Miller <davem@davemloft.net>