msm: emac: Avoid device suspend in case of link active

EMAC driver should not allow device to go into system suspend
incase Ethernet link is up. This is to avoid active xfer
failing over the Ethernet link.

If link is down then allow system to go into suspend state.

Change-Id: I5bd3fa58ca716ad0a1ab4a64a4fa3e43086e88c4
Signed-off-by: Alok Chauhan <alokc@codeaurora.org>