phyFLEX boards beginning with 1362.2 have a workaround for this
i.MX6 bug:
ERR006282 ROM code uses nonreset PFDs to generate clocks, which may
lead to random boot failures
On these boards the SD4_DAT3 pin os connected to the CMIC. The CMIC
will reset the board after 10s when the pin isn't toggled.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>