The check for is_imx6q was introduced initially in

	f1f6d76370b3 ("ARM: i.MX6: correct work flow of PFDs from uboot-sources")

to differentiate between i.MX6DL+i.MX6SL and i.MX6Q. The i.MX6D must be
handled like the latter, so drop the check. i.MX6DL+i.MX6SL can be
ignored here since since

	a66596282413 ("imx6: lowlevel_init: Fix workaround for new i.MX6s chips")

the PFD handling is only done for i.MX6DQ.

Update the comment to be not only logically correct but also helpful.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>