msm: kgsl: add api to limit gpu fmax

Existing api returns failure when requested frequency
is larger than fmax supported. This creates problem to
clients as they consider this as error case. This
can be improved if api returns success when requested
frequency is larger than fmax supported because requested
limit frequency is larger than fmax device will never
go beyond that at all and clients can execute normally.

Change-Id: Id1077ca03019a61d7fd6fef8eccd605131b9c150
Signed-off-by: Pranav Patel <pranavp@codeaurora.org>