vt: keyboard, rename i to kb_func in vt_do_kdgkb_ioctl

There are too many one-letter variables in vt_do_kdgkb_ioctl which is
rather confusing.  Rename 'i' to 'kb_func' and change its type to be the
same as its originating value (struct kbsentry.kb_func) -- unsigned
char.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20201029113222.32640-10-jslaby@suse.cz


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