MAINTAINERS: adjust MELLANOX ETHERNET INNOVA DRIVERS to TLS support removal

Commit 40379a00 ("net/mlx5_fpga: Drop INNOVA TLS support") removes all
files in the directory drivers/net/ethernet/mellanox/mlx5/core/accel/, but
misses to adjust its reference in MAINTAINERS.

Hence, ./scripts/get_maintainer.pl --self-test=patterns complains about a
broken reference.

Remove the file entry to the removed directory in MELLANOX ETHERNET INNOVA
DRIVERS.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>