clk: qcom: Add support to round the frequency to kHz

The divider round closest flag is designed for
the rounding to the Hz of the requested frequency.
Certain clock such as graphic clock on SDM845 needs
the divider to round to the kHz. This change support
this special round rate.

CRs-Fixed: 2048646
Change-Id: I1d5950faea30f94593321509dcf647af1b3fa57f
Signed-off-by: Vicky Wallace <vwallace@codeaurora.org>