dt-bindings: Add a clocks property to the simple-framebuffer binding

A simple-framebuffer node represents a framebuffer setup by the firmware /
bootloader. Such a framebuffer may have a number of clocks in use, add a
property to communicate this to the OS.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Mike Turquette <mturquette@linaro.org>

--
Changes in v2:
-Added Reviewed-by: Mike Turquette <mturquette@linaro.org>
Changes in v3:
-Updated description to make clear simplefb deals with more then just memory
simplefb: formalize pseudo palette handling

Signed-off-by: Luc Verhaegen <libv@skynet.be>
Acked-by: Stephen Warren <swarren@nvidia.com>
[hdegoede@redhat.com: drop unnecessary void * cast]
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
simplefb: add goto error path to probe

Signed-off-by: Luc Verhaegen <libv@skynet.be>
Acked-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
simplefb: add clock handling code

This claims and enables clocks listed in the simple framebuffer dt node.
This is needed so that the display engine, in case the required clocks
are known by the kernel code and are described in the dt, will remain
properly enabled.

Signed-off-by: Luc Verhaegen <libv@skynet.be>
[hdegoede@redhat.com: drop dev_err on kzalloc failure]
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>