net/mlx5: Fix MTMP register capability offset in MCAM register

The MTMP register (0x900a) capability offset is off-by-one, move it to
the right place.

Fixes: 1f507e80 ("net/mlx5: Expose NIC temperature via hardware monitoring kernel API")
Signed-off-by: Gal Pressman <gal@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>