net: stmmac: disable & enable clock on suspend resume

disable all eth clocks on suspend and enable them on resume.

Change-Id: I65e80188e2cce0967b5bce8f0f5f55c842f40aa0
Acked-by: Nagarjuna Chaganti <nchagant@qti.qualcomm.com>
Signed-off-by: Suraj Jaiswal <jsuraj@codeaurora.org>