drivers/tty/serial: Remove unused function early_mcf_setup

drivers/tty/serial: Remove unused function early_mcf_setup

Compiling a kernel for the ColdFire causes a compiler warning:

drivers/tty/serial/mcf.c:473:12: warning: no previous prototype for
 ‘early_mcf_setup’ [-Wmissing-prototypes]
  473 | int __init early_mcf_setup(struct mcf_platform_uart *platp)
      |            ^~~~~~~~~~~~~~~

This function seems to be completely unused, so let's remove it
to silence the warning.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Acked-by: Greg Ungerer <gerg@linux-m68k.org>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/r/20240219164002.520342-1-thuth@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>