net: macb: Add capability-based QBV detection and Versal support

net: macb: Add capability-based QBV detection and Versal support

The 'exclude_qbv' bit in the designcfg_debug1 register varies across
MACB/GEM IP revisions, making direct probing unreliable for detecting
QBV support. This patch introduces a capability-based approach for
consistent QBV feature identification across the IP family.

Platform support updates:
- Establish foundation for QBV detection in TAPRIO implementation
- Enable MACB_CAPS_QBV for Xilinx Versal platform configuration
- Fix capability line wrapping, ensuring code stays within 80 columns

Signed-off-by: Vineeth Karumanchi <vineeth.karumanchi@amd.com>
Link: https://patch.msgid.link/20250814071058.3062453-3-vineeth.karumanchi@amd.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>