IB/mthca: Coverity fix to mthca_init_eq_table()

Fix bug found by coverity: the loop body never executed, because it
was doing for (i = 0; i < MTHCA_EQ_CMD; ++i), but MTHCA_EQ_CMD is 0.
The correct loop bound is MTHCA_NUM_EQ, to loop over all EQs.

Signed-off-by: Roland Dreier <rolandd@cisco.com>