Use the console kernel parameter to also activate hvc0 to receive Linux kernel messages.
By default, the line-mode terminal device ttyS0 is activated to receive Linux kernel messages and also is used as the preferred console. Of the HVC terminal devices, only hvc0 can receive Linux kernel messages.
console kernel parameter syntax >>-console=hvc0------------------------------------------------><
You can specify multiple console statements, each activating a terminal device to receive Linux kernel messages. The last console statement specifies the preferred console. If the following is the only console statement in the Linux kernel parameter string, hvc0 is activated to receive Linux kernel messages and also becomes the preferred console.
console=hvc0
console=hvc0 console=ttyS0
For more information about the console kernel parameter see Device Drivers, Features, and Commands, SC33-8411.