Omnia: Enable earlyprintk for easier UART debugging
It was requested and provided by @prohar to set these kernel options:
CONFIG_CMDLINE="earlyprintk console=ttyS0,115200"
CONFIG_CMDLINE_FROM_BOOTLOADER=y
CONFIG_DEBUG_LL=y
CONFIG_DEBUG_MVEBU_UART0_ALTERNATE=y
CONFIG_DEBUG_UNCOMPRESS=y
CONFIG_EARLY_PRINTK=y