clk: qcom: Add support to force enable/disable the RCG

Some RCGs would be expected to be enabled/disabled using
the root enable bit of the RCGR. These RCGs would have to
indicate the force enable using the FORCE_ENABLE_RCGR flag.

Change-Id: Ia1eaba2728d06066612739ff48f7e5e44322e96b
Signed-off-by: Amit Nischal <anischal@codeaurora.org>