net/mlx5e: Fix matching of speed to PRM link modes

Speed translation is performed based on legacy or extended PTYS
register. Translate speed with respect to:
1) Capability bit of extended PTYS table.
2) User request:
 a) When auto-negotiation is turned on, inspect advertisement whether it
 contains extended link modes.
 b) When auto-negotiation is turned off, speed > 100Gbps (maximal
 speed supported in legacy mode).
With both conditions fulfilled translation is done with extended PTYS
table otherwise use legacy PTYS table.
Without this patch 25/50/100 Gbps speed cannot be set, since try to
configure in extended mode but read from legacy mode.

Fixes: dd1b9e09 ("net/mlx5: ethtool, Allow legacy link-modes configuration via non-extended ptys")
Signed-off-by: Aya Levin <ayal@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>