linux-imx

simplefb: Fix build errors when CONFIG_COMMON_CLK is not defined

Both CONFIG_OF and CONFIG_COMMON_CLK must be defined to be able to use of
clocks.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>