net: zynq_gem: Fix return type for phy...()

wait_for_bit_le32 returns negative value on failure. Fix phy...() to
handle these failures properly.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
1 file changed