MLK-11285-01 net: fec: handle WAIT mode issue for imx6qdl

MLK-11285-01 net: fec: handle WAIT mode issue for imx6qdl

This is a combination of commits 919d46e37e04 (ENGR00265935 net: fec:
add pm_qos to avoid cpu enter to wait mode) and 8a12c90c9974
(ENGR00313685-14 net: fec: check workaround for FEC_QUIRK_BUG_WAITMODE)
from imx_3.10.y branch.  It's added for imx_3.14.y branch to work around
imx6qdl issue ERR006687 (ENET: Only the ENET wake-up interrupt request
can wake the system from Wait mode).

Signed-off-by: Shawn Guo <shawn.guo@freescale.com>
(cherry-pick and merge from commit: 4f406fae257cc7945a0e3a425213440bb12ba345)