FP3: Re-enable CONFIG_SERIAL_MSM_SMD from prior commit

This is needed to create dev nodes for smd specific nodes and fixed failing Bluetooth:

    08-02 09:37:38.777 4727 4789 E vendor.qti.bluetooth@1.0-mct_transport: InitTransport: Cannot open /dev/smd3: No such file or directory 08-02 09:37:38.777 4727 4789 E vendor.qti.bluetooth@1.0-mct_transport: . Retry after 2 seconds

Change-Id: Ic9f3502f52af16ea46c221eb34ffdad1f9fb125b