ia64: select CONFIG_TTY for use of tty_write_message in unaligned

Fix breakage which will be exposed by the patch "kconfig: make allnoconfig
disable options behind EMBEDDED and EXPERT".

arch/ia64/kernel/unaligned.c uses tty_write_message to print an
unaligned access exception to the TTY of the current user process.
Enable TTY to prevent a build error.

Minimal fix, on the basis that few people on ia64 will care deeply about
kernel size enough to turn off TTY.  Ideally, I'd instead suggest
dropping the tty_write_message entirely, and just leaving the printk.
Bonus: no need to sprintf first.

Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>