msm: kgsl: Expose ACD table editing over sysfs

For Adaptive Clock Distribution (ACD) characterization,
a user must be able to change the ACD table that is
sent over HFI, using ADB. Expose sysfs nodes that can
be read and written for each field in the ACD table,
as well as for an index value that is used by the other
nodes to index into the ACD table data array.

Change-Id: I7a64968d866a3aa281bf68638b4083b46175de7b
Signed-off-by: Kyle Piefer <kpiefer@codeaurora.org>
Signed-off-by: Mohammed Mirza Mandayappurath Manzoor <mmandaya@codeaurora.org>