msm: copper: Temporarily stub out bus arbitration for copper

To unblock Multimedia and other bus scaling clients, stub
out arbitrated bandwidth settings for Copper until RPM
changes are merged.
Clock scaling code algorithm is unchanged, so clocks
can still be scaled as on 8960/8064/8930.

Change-Id: Iebeb631a47eed662761b12b696f1f37cc61ef54b
Signed-off-by: Gagan Mac <gmac@codeaurora.org>