net/mlx5e: Suppress Send WQEBB room warning for PAGE_SIZE >= 16KB

Send WQEBB size is 64 bytes and the max number of WQEBBs for an SQ is 255.
For 16KB pages and greater, there is always sufficient spaces for all
WQEBBs of an SQ. Cast mlx5e_get_max_sq_wqebbs(mdev) to u16. Prevents
-Wtautological-constant-out-of-range-compare warnings from occurring when
PAGE_SIZE >= 16KB.

Signed-off-by: Rahul Rameshbabu <rrameshbabu@nvidia.com>
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>