mlx4_core: Remove annoying debug message in the resource tracker

This innocent print makes it very hard to actually use the mlx4_core
debug messages -- for example, the module load sequence of a device
with two VFs yielded 3200 debug prints, with 2800 of them being this
one.  Let's just remove it.

Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>