net: fec_mxc: use simpler runtime cpu dection macros

Use simpler runtime cpu dection macros.

Signed-off-by: Peng Fan <van.freenix@gmail.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Joe Hershberger <joe.hershberger@ni.com>
1 file changed