net: stmmac: Add missing information in DebugFS capabilities file

Adds more information regarding HW Capabilities in the corresponding
DebugFS file.

Changes from v2:
- Remove the TX/RX queues in use (Jakub)

Signed-off-by: Jose Abreu <Jose.Abreu@synopsys.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>