clk: qcom: camcc-sc8280xp: Prevent error pointer dereference

If "regmap" is an error pointer then calling regmap_update_bits() will
crash.  We only need to call regmap_update_bits() if we had written to
it earlier.

Fixes: ff93872a ("clk: qcom: camcc-sc8280xp: Add sc8280xp CAMCC")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Abel Vesa <abel.vesa@linaro.org>
Link: https://lore.kernel.org/r/210d48ce-6ebc-4a6b-b30f-866d10d41a16@moroto.mountain


Signed-off-by: Bjorn Andersson <andersson@kernel.org>