hvc_console: fix test on unsigned in hvc_console_print()

vtermnos[] is unsigned, so this test was wrong.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>