clk: qcom: Fix slimbus n and m val offsets

These shifts were copy/pasted from the pcm which is a different
size RCG. Use the correct offsets so that slimbus rates are
correct.

Fixes: b82875ee "clk: qcom: Add MSM8960/APQ8064 LPASS clock controller (LCC) driver"
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Michael Turquette <mturquette@linaro.org>