vgacon: drop unused vga_init_done

Commit 973c096f ("vgacon: remove software scrollback support")
removed all uses of vga_init_done, so let's get rid of it entirely.

Signed-off-by: Stephen Kitt <steve@sk2.org>
Link: https://lore.kernel.org/r/20210215170837.1599706-1-steve@sk2.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>