Timing issue occurs on eMMC not only when modifying the frequency but
also for all the switch command(CMD6). According to the MMC spec waiting
8 clocks after a switch command would be the thing to do.
This patch allows fixing CPU hang observed when trying to changing the
bus width on a eMMC on SAMA5D4.
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com> Tested-by: Marek Vasut <marex@denx.de> # on DENX MA5D4EV Acked-by: Marek Vasut <marex@denx.de> Tested-by: Andreas Bießmann <andreas.devel@googlemail.com> # on atngw100 Acked-by: Andreas Bießmann <andreas.devel@googlemail.com>
[fixed minor checkpatch warning] Signed-off-by: Andreas Bießmann <andreas.devel@googlemail.com>