dts:seco:seco-genio-common.dtsi: mmc2 node added for sona mt320
mmc2 node added as it works with sona mt320, for this mt6359_vpa_buck_reg must be configured to supply 3v3 as always-on
mmc2 node added as it works with sona mt320, for this mt6359_vpa_buck_reg must be configured to supply 3v3 as always-on