net: zynq_gem: Use wait_for_bit with non breakable

Use wait_for_bit to be non breakable as using it with
breakable causes issue of un interruptible auto negotiation.
This is due to the ctrlc pressed will taken for wait_for_bit()
abort during phy_read() and hence not coming out of
auto negotiation.

Signed-off-by: Siva Durga Prasad Paladugu <sivadur@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>