dt-bindings: ufs: qcom: Add reg-names property for ICE

The code in ufs-qcom-ice.c needs the ICE reg to be named "ice". Add this
in the bindings so the existing dts can validate successfully.

Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230814-dt-binding-ufs-v6-1-fd94845adeda@fairphone.com


Signed-off-by: Rob Herring <robh@kernel.org>