net: phy: micrel: Add specific suspend

Disable all interrupts when suspend, they will be enabled
when resume. Otherwise, the suspend/resume process will be
blocked occasionally.

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>