net/mlx5e: RSS, Block changing channels number when RXFH is configured

Changing the channels number after configuring the receive flow hash
indirection table may affect the RSS table size. The previous
configuration may no longer be compatible with the new receive flow
hash indirection table.

Block changing the channels number when RXFH is configured and changing
the channels number requires resizing the RSS table size.

Fixes: 74a8dada

 ("net/mlx5e: Preparations for supporting larger number of channels")
Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://lore.kernel.org/r/20240409190820.227554-7-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>