Revert "ARM: dts: imx53-qsb-common: fix FEC pinmux config"

This reverts commit 2eb85ef1 which is
commit 8b649e426336d7d4800ff9c82858328f4215ba01 upstream.

Turns out not to be a good idea in the stable kernels for now as Patrick
writes:
	As discussed for 4.4 stable queue this patch might break
	existing machines, if they use a different pinmux configuration
	with their own bootloader.

Reported-by: Patrick Brünn <P.Bruenn@beckhoff.com>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>