net/mlx4: fix crash when configure is not called

net/mlx4: fix crash when configure is not called

Although uncommon, applications may destroy a device immediately after
probing it without going through dev_configure() first.

This patch addresses a crash which occurs when mlx4_dev_close() calls
mlx4_mr_release() due to an uninitialized entry in the private structure.

In addition MR cache init takes place on the device configuration.
When the device is re-configured multiple times, for example when
changing the number of queue on the flight, deadlock can happen.

This patch moved MR cache init from device configuration function to
probe function to make sure init only once.

Fixes: 9797bfcce1c9 ("net/mlx4: add new memory region support")

Signed-off-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>
Signed-off-by: Xueming Li <xuemingl@mellanox.com>
Signed-off-by: Yongseok Koh <yskoh@mellanox.com>