net/mlx5e: Remove DMA address from mlx5e_alloc_unit

net/mlx5e: Remove DMA address from mlx5e_alloc_unit

mlx5e_alloc_unit stores the DMA address and a pointer to either struct
page (regular RQ) or struct xdp_buff (XSK RQ). This DMA address is
redundant, because when a page or an XSK frame is allocated, the same
address is also stored there. Some flows take the address from struct
mlx5e_alloc_unit, and some take it from struct page or xdp_buff.

This commit removes the address from struct mlx5e_alloc_unit, which
makes it twice as small and improves locality (this struct is used in an
array), also saving on unnecessary stores to the addr field. Almost all
flows know unambiguously whether the DMA address should be taken from
page or from xdp_buff. The exception is the allocation flows, where a
new branch appeared, which will be optimized out in the next commits.

struct mlx5e_alloc_unit used to be called mlx5e_dma_info.

Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>