tty: hvc: fix link error with CONFIG_SERIAL_CORE_CONSOLE=n

aarch64-linux-gnu-ld: drivers/tty/hvc/hvc_dcc.o: in function `dcc_early_write':
hvc_dcc.c:(.text+0x164): undefined reference to `uart_console_write'

The driver uses the uart_console_write(), but SERIAL_CORE_CONSOLE is not
selected, so uart_console_write is not defined, then we get the error.
Fix this by selecting SERIAL_CORE_CONSOLE.

Fixes: d1a1af2c

 ("hvc: dcc: Add earlycon support")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20200919063535.2809707-1-yangyingliang@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>