clk: qcom: clk-rcg2: Add enable & disable callbacks for RCG floor ops

If enable safe config is true and a rate scaling request comes
while RCG is in disabled state, RCG's new configuration update
would be done as part of enabling the RCG. Hence add the enable
and disable callbacks for floor ops to properly configure the RCG
in all cases.

Change-Id: I3621e0dd2cb948cb523cd85659d0de0359ba5829
Signed-off-by: Jagadeesh Kona <jkona@codeaurora.org>