[x86] Use Roman font style banner for x86_64_generic host

This patch enables Roman style banner for x86_64 generic host via
defconfig (just like ARM boards).

Signed-off-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Himanshu Chauhan <hschauhan@nulltrace.org>
[x86] defterm: Add support for delete, backspace, left and right sequences

This patch adds supports for printing VT100 escape sequences such as delete,
backspace, left and right in x86 defterm.

Signed-off-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Himanshu Chauhan <hschauhan@nulltrace.org>
Merge x86-next from https://hschauhan@github.com/hschauhan/xvisor-x86_64.git