arm64: dts: qcom: qrb4210-rb2: make L9A always-on

The L9A regulator is used to further control voltage regulators on the
board. It can be used to disable VBAT_mains, 1.8V, 3.3V, 5V rails). Make
sure that is stays always on to prevent undervolting of these volage
rails.

Fixes: 8d58a8c0 ("arm64: dts: qcom: Add base qrb4210-rb2 board dts")
Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20240605-rb2-l9a-aon-v2-1-0d493d0d107c@linaro.org


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