mlx4: add missing braces in verify_qp_parameters

The implementation of QP paravirtualization back in linux-3.7 included
some code that looks very dubious, and gcc-6 has grown smart enough
to warn about it:

drivers/net/ethernet/mellanox/mlx4/resource_tracker.c: In function 'verify_qp_parameters':
drivers/net/ethernet/mellanox/mlx4/resource_tracker.c:3154:5: error: statement is indented as if it were guarded by... [-Werror=misleading-indentation]
     if (optpar & MLX4_QP_OPTPAR_ALT_ADDR_PATH) {
     ^~
drivers/net/ethernet/mellanox/mlx4/resource_tracker.c:3144:4: note: ...this 'if' clause, but it is not
    if (slave != mlx4_master_func_num(dev))

>From looking at the context, I'm reasonably sure that the indentation
is correct but that it should have contained curly braces from the
start, as the update_gid() function in the same patch correctly does.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 54679e14 ("mlx4: Implement QP paravirtualization and maintain phys_pkey_cache for smp_snoop")
Signed-off-by: David S. Miller <davem@davemloft.net>