ARM: mx5/mx53_evk: Make the reset pin name more meaningful

As there is a mx53_smd board in the kernel, using SMD_FEC_PHY_RST as the pin name can be misleading when used
on a MX53_EVK board.

Change the pin name to reflect the board name.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>