tty: sparc: rename drivers/tty/serial/suncore.h -> include/linux/sunserialcore.h

There are multiple users of this file from different source
paths now, and rather than have ../ paths in include statements,
just move the file to the linux header dir.

Suggested-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>