net/mlx5: define MPRQ functions as static inline

net/mlx5: define MPRQ functions as static inline

Functions mlx5_check_mprq_support(), mlx5_rxq_mprq_enabled(),
mlx5_mprq_enabled() are moved from source file mlx5_rxq.c to header file
mlx5_rxtx.h and their type is updated to 'static __rte_always_inline'.
Previously the functions were declared as 'inline' in the source file
which was reported as 'unresolved external symbol' error by some Windows
linkers.

Signed-off-by: Ophir Munk <ophirmu@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>