uboot-imx

imx6: clock: Enable External Memory Interface [EIM] clock (eim_slow_clock)

This patch extends the imx6 clock code to enable or disable the EIM
slow clock, which in necessary when one wants to use EIM interface t
o read/write from external memory (e.g. NOR).

Signed-off-by: Lukasz Majewski <l.majewski@majess.pl>