MAINTAINERS: Remove unused Qualcomm SoC mailing list

This patch removes the linux-soc mailing list from the Qualcomm SoC
entry.  We use the linux-msm and there is no need to have the second
one and this clears the list for use by others.
Signed-off-by: Andy Gross <andy.gross@linaro.org>
Signed-off-by: Olof Johansson <olof@lixom.net>

MAINTAINERS

@@ -1922,7 +1922,6 @@ ARM/QUALCOMM SUPPORT
 M:	Andy Gross <andy.gross@linaro.org>
 M:	David Brown <david.brown@linaro.org>
 L:	linux-arm-msm@vger.kernel.org
-L:	linux-soc@vger.kernel.org
 S:	Maintained
 F:	Documentation/devicetree/bindings/soc/qcom/
 F:	arch/arm/boot/dts/qcom-*.dts