net: stmmac: marker for suspend/resume

Enable support for Ethernet Link UP KPI marker for
as part of system resume.
Currenlty Ethernet Link up KPI marker is printed
once once & print flag is set to true to avoid further
Link UP KPI print. This flag need to reset as part of
suspend to print the Ethernet Link UP KPI marker at resume.

Change-Id: I849a76520c4c619255ba650fff546a32a05adc2e
Signed-off-by: Suraj Jaiswal <jsuraj@codeaurora.org>