lspci: Add Lane Margining support to the lspci

lspci: Add Lane Margining support to the lspci

Gather all the info available without writing to the config space.
Without any commands margining capability exposes only 3 status bits to
read through Margining Port Capabilities and Margining Port Status registers.
It makes sense to show them anyway. For example, Margining Ready bit
indicates whether the device is actually ready for the margining process.

Reviewed-by: Sergei Miroshnichenko <s.miroshnichenko@yadro.com>
Signed-off-by: Nikita Proshkin <n.proshkin@yadro.com>