powerpc: Make open count variables signed in hvcs/hvsi/hvc_console

Otherwise the tests for count < 0 will never be true.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

diff --cc drivers/char/hvc_console.h
Simple merge

diff --cc drivers/char/hvcs.c
Simple merge

diff --cc drivers/char/hvsi.c
Simple merge