arm64: dts: qcom: sm6350: Fix naming of uart9

The uart9 was previously mistakenly called uart2. Fix this.

Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220408114205.234635-1-luca.weiss@fairphone.com